You can use slime blocks as an instant way down. (When landing on a slime block, hold your jump button (space bar) and it'll break your fall and prevent you from being trampolined.) I'm not sure about a way up, because a slime block isn't powerful enough to boost you up into your floating base. (120 blocks fall onto slime block ~ 50-75 blocks trampolined.) You can always cheat and do "/give [playername] command_block 1" and put it under your floating base so you can command it to teleport you up there.
Hit Counter(Included in all of my media sources a.k.a forum sigs and ect): Since 2nd of May 2015
Sorry about too much photos.