Portable tables are not very stable.  You could go with pre-feb benchwork but that can be expensive.  

How about hiring a carpenter or handyman to build simple benchwork/table for you? 

I used 3 of them on my new layout. Got them at Target $30.00 each. 6'x30". Because they have a plastic top I went 1" insulation,3/4" partical board for strength, and one more 1" insulation. I am very pleased with the sound. 10'x9' layout. 

I have four layouts because of space limitations.  One is an 8 ft. X 16 ft. benchwork, one 4 ft. X 8 ft. benchwork, one 4ft. X 4ft. on a stationary table covered with plywood, and finally one on a 6' X 30" folding table covered with ceiling tiles.  All methods are working great for me.

My neighbor used a fold up  5' X 9' ping pong table on casters which folded up neatly and rolled away.  For your situation consider Mianne Benchwork.  You have all the tools you will need already to assemble it.

I'm using a lot of 2'x4' folding tables on my layout a few other sizes and tables I had around the house. The ones I went with had the plastic top. If you go that route these tables aren't completely flat and sort of dip in the middle. Because of that I've had to shim up my tracks in some places. I went with this setup because it was fast and easy. Here's some photos of when I was setting it up almost 3 years ago.

I think part of the answer depends on how large a layout you are building. If it's small, folding tables might be acceptable, but personally I'd go with a simple ladder frame wood construction that doesn't need many power tools - a good circular saw and portable power drill should do it.

And  don't forget that the big box stores will custom cut your plywood and framing lumber (1 X 4's, 2X 4', etc.) into any size/length you want, so if you have a well thought out plan and know the dimensions you need, you could go to Lowes or HD and pick everything up and have it cut to your measurements (make sure to tip the nice gentleman or lady), bring it home and just assemble everything with little or no cutting on your own.  

i got a used folding poker table with sturdy metal legs -See if that works.

Sal V. posted:

i got a used folding poker table with sturdy metal legs -See if that works.

I'm guessing you're kidding but I actually do have 2 old metal poker tables with the cardboard top as part of my setup. However for those I did add a piece of plywood on top.

The folders wobble a lot and that's bad.  However; a couple of L brackets to a wall stud would hold nice. (or round tube; conduit and pipe brackets)

(and transmit sound; adding rubber washers between surfaces and bracket would help tons. Maybe even nylon hardware; you aren't building a battleship.

 Common hex screwdriver bits work well in most drills (carefully, & longer bits are usually easier to keep chucked) So an electric screwdriver isn't always needed...kinda rare today imo actually; the cordless drill rules that roost now...but a corded drill works too.   (mind you add pilot holes too and you stop split wood.) 

Use high quality threaded wall anchors (1 or 2) and a couple of finger/ wing bolts and it could be taken down fast; no tools.

One cheapie 36" dia metal tube & vinyl on hardboard type card table

A.K.A- "The Drink Spiller" 🙄

But everything on it is very lightweight; power supply etc on a phone stand 12x15"?.

I used a workbench frame from Global Industrial Supply.  Check out their Bench Legs, Frames, Stringers and Uprights.  I built a 5' X 9' N-Scale layout on top of one.