I managed to look into Mystcraft. I'm going to say "no" that Thaumcraft rune portals don't transport you across worlds. This is because the world change incurs a loading screen, and that's a bit beyond normal capacity. To the same degree, it's likely that runic portals don't transport you to distance chunks, unless you've placed a chunk anchor of some kind (Railcraft and Thaumcraft both have anchors).
I started toying with Mystcraft. Found a world of tiny forests of perpetual night. It was interesting, very serene. Next was a world of massive biomes, desert, constant rain, and perpetual noon. This one had a lot of oil, and several Thaumcraft obelisks. After that was an endless prairie in mid-day, and then an ocean in mid-day. The final book I attempted resulted in a crash, so I assume that it was a pretty amazing world. It took my inventory with it, including a bunch of resources I really liked. Ragequit, new world. I know what many technic mods do now, so this will be a "real" world.
How do you create custom worlds in Mystcraft? I collected a few symbols, but couldn't figure out any writing ability.
Also worth noting: Thaumcraft runes work well with IC2 agriculture. The IC2 crops are annoying because you can't walk over them, even sneaking will cause them to break pretty quickly. So I set up some crops along a wall, and then a Thaumcraft rune of air-evil-evil, which will suck in nearby items and deposit them into a chest. Turns out to be pretty great. Next I'm gonna try doing a wheat farm with runes, but I'm not entirely sure the setup I want to use. It really depends on if the "tills soil" and "hydrates soil" runes work by line of sight, or by proximity. They're probably LOS, so I'd have them suspended from the ceiling above the crops. I'll have to see if they can't be attached to lamps, because it'd be pretty fun to have the whole thing inside and use artificial lighting.