how about a vt?
 

trying to decide which bike... 80/100GS or a big single which is lighter.
Had a thought (ouch) previous bike owned for a short while was a Honda VT 500. A light weight, narrow v twin with shaft drive.
The Honda didn't give me any problems in the 12 months or so ownership so how about 'converting to dirt' the above?
Just wondered if anyone had any views, experience on the subject.

One of the biggest problems with converting a street bike to dirt is finding dirt tires that will fit a street bike.
Check your wheel sizes.

I'm not sure if you still have the VT500, but if you do, and you are looking to keep on the road cheaply, then I'd stay with the Honda ( especially if it has been looked after ).
That engine saved Honda from ridicule back in the eighties ( ask riders of that era about chocolate camchain tensioners and exploding CX /V4 engines) and its off-spring are considered some of the most reliable bikes on earth - the Transalp, Revere ( NTV 600/650 ).

One other advantage is that, as an old bike, it should be much, much cheaper to obtain the carnet and insurance for.

Beefing it up for off-road use may be limited to fork springs and shocks. You could consider the Transalp, though.