Lionel fastrack layout help

Here are two I did last week for another thread.  They allow for two trains moving at once, and a place to park another train and have lots of spurs to put things.  If you go with a different track, like tin plate or Atlas, you could fit more action in, IMHO.  Also depends on the minimum curve requirements of your rolling stock and locomotives.

No problem.  Get a copy of SCARM (It's free.) and play with it to see what you come up with.  If you go up you can get another loop or two in.  I might toy with that at lunch.

Here's a version with a wye to change directions. 4 switches 1 crossover.

Plenty of straights for accessories. Two trains at once would be exciting to avoid collisions. Could put detection relays in, but pretty much a single train setup.

Room to expand with yard stubs or passing siding.

Higher scenery\accessories  to track ratio.