Somebody beat ya to the punch. Er, topic. I believe what you're looking for can be found here.
@Winter. Because I'm Winter. Period.
I am a blaster first, and an alt-oholic second.
you're right, I saw that thread afterwards. Mine is slightly simpler. A vendor wouldn't hurt tho, like a simple auto-doc vendor from bases. Also, all players should get the temp travel to league staging area power, not just 50s. The hangup I see to both solutions is being able to invite to a League from intermingled teams. So, someone will need to get to a neutral zone to be invited, or maybe (light bulb moment...)
DRUM ROLL PLEASE>>>> The temp power takes you to a staging area, generic, hallway. from there you can be invited to your league, and move down the hall and into the door where you go to league staging area for your league to meet your league mates.
TA Da DA DA DAAAH Da Da DAAAAAAHHHHHHHHHHHHHHHHHH
We all know about crowding in RWZ1, 2, 3, 4, etc. as leagues set up. Why not give every player in the game a power like Pocket D pass, or vet base teleporter? the power would be good only for teleporting to a "staging area" base that is only used by that league. In case there is any difficulties, also have the staging area door accessible from RWZ and Pocket D, maybe Midnighter Club and Ouroboros too just to make it easy. The staging are base would be bare bones, pretty much a simple area with a few decorations (very few) so that it loads fast and can just be used for getting everyone ready for the trial. A military cargo hanger with a few shuttles prepping for launch might fit the theme.