Look in the crafts dept at Wally world, they have thin foam sheets, they work great on your work bench. Perfectly straight and you can easily put pins in.
And it's a good idea to put wax paper over your plans. The bench you have is a good start, maybe you want to pick up another table or bench, you'll be running out of space soon and putting things on the floor can be fatal for them...

As far as tools go, a Dremel helps a lot, a cordless drill and a sander will help a lot (I bought a hand sander at HF for $10 and it works great).
You will find yourself running to the store while you build your plane, there is always something...I'd make sure I got all the parts you can't get at a local store like wheels, tank, spinner, covering.

Also you will need an iron for the covering.