you could do something similar to this.but it be too big in redstone…..if you wanna go for it anyways heres a small idea:

you can make a sign  activate a machine.the machine could open a piston door that has a normal door behind it.a clock that will circle around the place for 1 minecraft day could be made .to sinel that the room is taken there would be a lamp that’s activated will this is happening. and if you do this  it could only be truly save if you had a enderchest inside and a bed.

heres a more simple idea:

theres this sign that lest you activate a machine.what the machine does is open a staircase that taskes you to the room,this  opening will only lasta few seconds…..after that a piston will remove the block that allows it to be reactivated.once that happens a clock will activate this will last 1 minecraft day and then another piston will reinstall that block and the machine could be reactivated.do note this machine is still gonna be huge…..but its  as simple as it gets wit out a plugin or a mod….