More like... except there isn't any "provided". Every point on Earth has a "nearest nexus", the only way you could potentially have problems is trying to teleport into a nexus-less dimension.
DB7p14 for example has 1/5 of all dimensions as "no magic energy" with no ley lines (and thus no nexi... not sure why they felt the need to list that separately) where it costs twice PPE to cast magic. That's probably a good assumption to take for a tech-heavy setting like Recon, maybe even Splicers? It might be appropriate to apply that to pocket dimensions/envelopes too. It makes sense since there wouldn't be lines in them and would discourage spellcasters to do stuff like hide in the dimension and power up a bunch of spells, due to the doubled cost.
I would've thought Systems Failure but it specifies on the next page it's a "Low Magic Energy" world like pre-Cataclysm "Rifts" Earth, BTS and HU (kind of fuels the speculation about Rifts' past being a BTS/HU parallel of sorts).
- - -
The Wujcik settings (TMNT / ATB / N&SS / MC) don't get mentioned, but I'd probably peg them here too. Same with "Dead Reign", due to the magical-ness of the zombies.
Nightbane is also not mentioned, I'm wondering if it belongs in the prior, or maybe in the next "Intermediate Magical Energy" like Hades + PF (no mention of Dyval, but guessing it's also this). Perhaps it differs like Nightbane Earth is Low while Nightlands are Intermediate?
Guessing "Chaos Earth" would be a "Super High Magic" just like Rifts. That's the highest (1 in 100) category. Chaos Earth might even be a theoretical category above this? There ought to be a higher category, after all PF2p277 ranks the "Age of Light" as possibly 10-50% greater than Rifts Earth (that sounds about right for Chaos Earth too) while "Age of Chaos" was "easily ten times more powerful" than Rifts Earth (I think the Old Ones had a monopoly on that kind of power)
I think if you roll 100% for "Super-High" you should roll a 2nd time, with 1-89 being normal Super-High (like Rifts), 90-99 being Mega-High (like Chaos Earth or Age of Light) and 100% a 2nd time (1 in 10,000 dimensions) being Ultra-High (10x Rifts, like Age of Chaos).
- - -
Pg 15 of course says Wormwood is a "high magic" dimension (it and Phase World are both just a step below Rifts) with deeply buried lines/nexi (inside the planet rather than atop it... or maybe it's atop some smaller planet with wormwood flesh grown atop it?) so that causes an interesting consideration for Shifters like Salome who might use their power to teleport back to Wormwood from a place they might visit often, such as the Homeworld of the Demongoblins...
My guess at why this hasn't happened (or has it?) is that a similar-but-unwritten "you don't fall into the ocean, you don't get stranded in a desert" policy might govern "6." like it does "4.", so Salome will appear far enough away from the nearest nexus that it doesn't strand her inside the solid body of a planet, causing instant death like a bad teleport.
On Rifts Earth, this should also prevent problems like rifting smack into the flesh of a Millennium tree parked on the nearest nexus to your intended destination.
In her case, I would assume that the destination would thus be the nearest cave. Since caves act like being near a ley line (and not a nexus) I'm thinking this means that the thickness of wormwood around nexuses is much thicker (more than 200 feet) whereas there are points where wormwood's lines could be covered by somewhere between 1 and 199 feet of surface-flesh.
- - -
Anyway, since there are places with "nexi buried in concrete" (so to speak: Wormwood) or "no nexi" (20% of all dimension, "No Magic") we definitely need a way to resolve how that affects this ability.
I suggest floating 4's protections to 6 to avoid situation 1. Although it's not 100% necessary: it's not true teleportation, you always have the option to just not step through the portal. Perhaps to enjoy the "no oceans or deserts" benefit, the more expensive ability 4 ought to be used?
As for situation 2, you could simply say that you just can't use the ability and must use a more expensive ability that doesn't imply a need for a nexus-bus-stop, such as ability 4, or the Dimensional Portal spell.
There might be ways around this problem. Some ideas:
1) hire a Nazca Grand Master to Create Ley Line twice ("X marks the spot")
2) teleport a huge chunk of planet into another dimension, perhaps ley lines come along for the ride?
3) create a coexistence phenomenon between a place that has a nexus and the nexus-less dimension (like in Yucatan, or Psyscape)
4) build Stone Pyramids OFF of ley lines.
Re the last point, I've been under the assumption a long time that a pyramid must be touching a ley line, but I'm re-examining that assumption right now.
Atlantis 104 establishes there are such a thing as pyramids with "NO mystic powers!". Specifically this is what happens when you build more pyramids on a ley line beyond the 1 per 5 miles. I assume this is tip-to-tip, otherwise you could have smaller gaps between larger pyramids if it was measured between their centers.
As such... there could also be no-powers pyramids built off of ley lines. Reading 104's "Pyramid Technology" I can't see anything forbidding this, for example.
"All stone pyramids are mega-damage structures" is listed under ability 4 (the focus and control of available PPE) so despite "all", since it's mentioned under "The Powers of Stone Pyramids" (or POSP) it may not apply to these superfluous "late additions" pyramids, and thus not to Pyramids built off of ley lines either.
Of course even without being MDC, SDC pyramids could still be pretty sturdy structures.
Perhaps Salome has one of these stashed somewhere on Wormwood allowing her to use ability 6 without opening pointless portals into the nexus-flesh of the planet?
- - -
DB7 p 70 mentions for Spires:
Shifters who are familiar with the Dimension of Spires think of it as a "backdoor" to any continent on Rifts Earth, and use it to travel to specific destinations.
This appears to imply that Shifters have difficulty traveling to specific destinations. We know how unspecific (4) is and I don't see any reason to think that (6) would necessarily be ultra specific.
We do already know that (6) does have a specificity advantage over (4), as 'nearest nexus or pyramid' is a lot better than 'same planet' or 'same continent' and could sometimes be better than 'within 200 miles' (I'm a little unclear how frequently we find nexuses in certain areas of the world). With it already being that much better, I don't think it needs to be any more accurate than that.
This could explain why a Shifter might prefer to use Spires: go there often enough that you can "Dimensional Teleport Home" there, and then walk your way to a specific portal to a known destination that may not necessarily be a nexus or pyramid.
It also makes setting up "Circle of Travel" next to major pyramids/nexuses very valuable, since then you could hop through those rifts to get to more specific places away from nexuses without needing to go full DP.