I finally sent a rescue mission to laythe and returned with my 6 kerbals who landed on the surface. Pretty crazy mission all up when you think about it. Flying to the Jool system with the lander and plane, 2 landing, re-orbits and rendezvous, sending another ship to the Jool system, rendezvous with the original ship in orbit around laythe, then flying all the way back to kerbin, capture of the ship and circuliarzation of it on a Low orbit for future reuse.
Edit: some Pictures
Rendezvous with the original mother ship in laythe orbit
Saying goodbye to Jool on the way home
Saying hello to kerbin!
The full team infront of "mockups" of the space plane and lander that landed on Laythe. On the left is Jeb in-front of his SSTO space plane. The next 3 are the pilots of the original mother ship, and the next to the pilots of the rescue mother ship. On the right are bill and bob in-front of their lander that they used to Land on and return from the surface of Laythe with.
All in all. while there was a lot of complexity to this mission, there wasn't anything particularly massive about it. Due to the fact that kerbals still require just a pod, with no lfiesupport or food, its pretty easy to send them on long trips. However given the fact I managed to send a SSTO and a Lander along with them on the first, albeit not powerful enough mothership, i'm confident that in future i could design a manned mission to Jool with whatever life support constraints imposed, but i'm not sure i could do one with 2 landers aswell, particularly with the new reentry heat and aerodynamics probably going to make such landing and ascent missions much, much harder in future.
Alternatively, setting up some sort of fuel processing base on Vall might be a good way to allow a smaller transfer craft to be used, and almost unlimited local exploration be done.