Why won't the guard let me go anywhere?

Because only tentacles have rights in this future.

So you need to make yourself look like a tentacle.

It's too bad that you don't know how to make costumes.  But one of the
other people in the game is famous for sewing.

Betsy Ross in Hoagie's time is your woman.

Didn't she tell Hoagie that she'd make the next plan that she received for
a new American flag?

So give her a plan of a tentacle.

There's one in the doctor's office along the wall.

Flush it from Laverne to Hoagie and pick up the flag/costume.

You'll only find the flag on the roof of Laverne's time.  Go through the
door on the back wall of the hotel lobby in the future and then crawl through
the fireplace to reach it.

All you need now is a crank to operate the flag pole.