Hey does anyone know how to make a base for TFs (Like Ocean city or the volcano in G1)

Lots of time and construction materials...

Cardboard and Styrofoam :P

find a place in your yard that doesnt have a lot of bugs

putty and legos!

If you start by constructing the city out of wood, get most the details that you want, spray on a non-stick surfacer then cover it with a cloth sheet. Then apply liquid fibreglass resin to it and allow to dry. Once dry, you peel it easily off of the wood and reinforce it with fibreglass matting sheets and resin to stengthen it from Decepticon attack. Using fibreglass will make it light and easy to stow away, and be hollow to put figures inside. With this done, you can now cut blast doors and windows with a cut-off wheel to keep the edges clean. For artillery, you can steal your brothers paintball or BB gun and mold it in using a sealed bearing and a cupboard hinge. A mig welder will be needed to make the gun permanent so it doesn't fall off. If you can get some old hydraulics from a lift gate, you could use them to make parts move magically. DO NOT USE DUCT TAPE, it is a fools tool, sure it will last a little while but eventually lets go. You now sand the whole thing and grind in the details in order to apply the primer coat. Allow to dry and sand again with a finer grit. Spray entire city with appropriate base colour then clear with a flattening agent to knock down the gloss. In order to power an energon grid, you'll need some chicken wire and a 12v car battery. I'm just messing with you. Cardboard is the best way. If you bothered reading all this then you must really want to build one.

LOL sadly, I did read all that, that.

Thanks guys and I have BB and Paintball gun

NO dood, don't do it, I was only kidding. Last thing I need is some dead kid on my hands, use a water pistol instead, then you won't need a MIG welder, just a tube of plastic repair from Duramix part number 48786545 which sells for $34.95 Canadian or about $5.00 US.

I say figure out how to build an Ark, and then look online for how to build a working volcano for like science projects, increase the size as necessary, and slide the Ark in there and have your own fun :)