Does anyone have plans/suggestions for a simple freestanding door prop. It needs to be the size of a normal door (front door of a house), and be practical, lightweight and stable. In visual terms it doesn't have to be totally realistic as we are doing a production which involves a slightly cartoon-y style of set. But it must open and shut, and mustn't wobble (well, mustn't wobble too much).

Ideas gratefully received.

When we've done this sort of thing, we've been able to screw the foot of the frame to the stage (using a couple of angle brackets), and brace the top of the frame to a wall behind the door by means of a couple of long stays. (We had a window frame mounted on top of the door to give a total height of around eight feet, so the braces were run from the top of the window frame to an eight-foot flat at the rear.)

Ah, I forgot to mention one thing - it's for a one act play festival, which means that we have no more than ten minutes to install the set and five to strike it. And we can't screw it to the floor for the same reason. The rest of the set is quite simple, though.

In which case, the frame needs to be attached to a flat base. Frame offset towards the front of the base and a couple of braces triangulating from half way up the frame stansions to the rear of the base. Carry it on pre-assembled. A couple of hefty stage weights on the base.
Given that you want the door to look like a door, it has to be hung properly, which implies that the door is, in fact, a door! (That means getting the lightest interior door that you can find in your local DIY shop - usually some sort of clad frame - and painting it to look like an exterior door.)
Teach your actors not to slam it!

The other option would be to hinge two fold out triangular braces to the back that can be swung into place on stage - a bit easier to transport than the flat plate idea. You can then hook a cross piece between the two to stop them slipping away from each other sideways.

A door flat with french braces & a couple of sandbags to counterwiegt the braces & wieght of the door swing.
Hinge the braces on the back of the door flat, so they swing up stage to brace the flat. If you can use soft flats, rather than the TV hard type.
Or make up a door flat, by putting the width of the wood used in the frame, so the wood lays flat & not on it's edge, as with a normal flat. The skin can be applied in the same way, but the flat side of the frames wood would give more stability on the deck & require less bracing.

Why not have a empty frame and pretend it's a door?

Get the actors acting...

Bewdy George!
What you could do is under screw to the door frame a flat board, this would stablise the flat. Or use boom footing plates ['Tank traps'] , by attaching pipe sadles on each side of the door flat frame stiles upstage & then sliding the flat onto the 'tanktraps'. The pipe in the footing base plate, would slide into the sadles & hold the door flat secure.
You could still use the sandbags & incorpate the hinged french braces, as suggested by others.

My answer to anything set based is to use fabric - light tube frame with painted fabric door