need to replace windshield frame and rear top frame

[mrlmd]

Because of where I live, right on the Gulf Coast on the water's edge, everything metal that I own is rusted beyond belief despite frequent derusting, Ospho, and paint. My windshield frame and rear top frame has rusted beyond belief and is about to break and crumble into many pieces as well as dust, and I need to replace the frame or make a new one, maybe out of copper pipe. My problem is getting the old one off, getting access to the bolts underneath attaching it to the body. I may just have to cut or grind the bolts off as they are so rusted there is probably no way to get them apart. My basic question is how to access the nuts underneath the body. I see no way to get the dashboard off and cannot reach them from underneath the front or side of the cart. The rear frame bolts are probably easier to get to from underneath the back of the front seats when you raise the seat.
The reason I want to access the area underneath the front frame is to be able to attach a new one, or as an alternative I could attach it to the side of the cart below the windshield at the front of the passenger compartment.
My cart is a 2001 Fairway Villager, serial # DG1031-041788.
Any suggestions would be appreciated.
Thanks.