On my '68 C model, I can handle 500 lbs. in the front seats and 50 gals of fuel. That puts it right at the forward limits (checked on Fltplan.com weight and balance as well as my own paperwork), and it still leaves it under GTOW by 155 lbs. As the fuel burns off, the CG moves forward, but so does the limits. I've had well over 400 lbs. in the front seats along with full fuel and some cargo, and she handled quite well. I'm over 220 lbs. and so is a friend I've taken flying, and we had no trouble fitting.
As for room, the Mooneys have more shoulder room than most singles in their class. Getting in and out is still a problem though, and would cause a lot of excitement in an emergency.
The hardest thing for me is reaching the fuel selector, but I have an extension for that now that makes it easy.