You probably won't find much about a 34-year-old TT. But you don't need to know much about the actual Roustabout brand trailer.
You can look at the tires and wheels and determine the size and you need to replace them.
You can look at the axle(s) and decide the brand name to check out for replacements, and measure the length of the axle from hub face to hub face to determine the length of the axle. (The hub face is the side of the hub which the wheel touches when bolted onto the hub.)
The Federal Certification label may still be on the front of the trailer or on the hitch to tell you the GVWR of the trailer. Then use the trailer's GVWR to determine the weight rating of required tires, wheels, axles, and suspension (springs?).
Or if the GVWR is not found, then use the weight rating of the wheels and tires to determine the approximate GAWR of the trailer. Then use that approximate GAWR to decide on the max weight capacity of new tires, wheels, axles, or suspension. I prefer my tires to have at least 20 percent more weight capacity than the axle(s).
If the trailer needs new brakes, your best bet is to replace the entire axle with one that has new brakes included. Probably about $300 per axle at
Trailer Parts from trailerpart.com
Components inside the trailer are generic and not made by Roustabout. It probably has a Dometic, Atwood, Norcold, Suburban or other common RV brand for water heater, stovetop, oven, reefer, AC, furnace, water pump, etc. So if you need to replace any of those components, remove the old one and measure it exactly, then go to any RV supplier and find a suitable replacement of any brand that will fit.
I'll bet you don't have a microwave in that old trailer, but any brand will do if you want to add one on the cabinet top. But stick with an RV microwave, because they are built to withstand more shaking and banging around than the cheaper ones for a house.
One good online source for most RV supplies is PPLMotorHomes. I'd start there, and if they don't have what you need then Bing or Google RV components to find other sources: