Welcome Dan! It looks like you have a 1985 T-2461. It looks like it hasn't seen much sun or weather either, because it looks like I spot a VIN sticker outside on the front corner. Not many of those have survived now.
Converting to a utility trailer isn't really advised. These frames are not designed for strength without a trailer on top of them. There isn't a lot of structure to the frame without the wood floor and box on top. It's possible to do such a conversion, but you're far better off buying a trailer designed for hauling loads.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR