Congrats on your new coach! For a 2000 model, the cost to repair the unit is just too high to make it worthwhile for an insurance company. The biggest issue is the lack of available striping and aluminum sourcing. There's just so many different crimp styles of aluminum siding that finding the correct one isn't easy, especially now that Sunline is out of business. Yes, it's possible to re-side the entire trailer, but it costs a lot more. There are ways to just do a section and still prevent water from coming in, but it takes a level of artistry that insurance repair places won't take the time to do.
I've been seeing a lot lately get totaled in NY/VT/PA due to all the flooding out there, so it sounds like yours got off pretty good. Perhaps you could find one of those with some good aluminum?
The 2753 model number is just a floorplan designation. I like this question, I don't think it has been asked before. The length is roughly 27', but in some cases, that's the target length when they start designing it and it can change slightly after that. In your case, your year and model come in at 27'7" total. But as a whole, yes, you can assume the first number as the approximate length.
The latter part of the model number goes way back to 1983 when Sunline converted to the modern model number style. There are many types of model numbers and many in a series. The 53 lies in the 50 series, which are rear bedroom models. A Model 50 typically defines a rear bedroom with a rear lounge and flip up tables, and the lounge pulls out into a big bed. A Model 51 indicates a rear corner double/queen bed. A Model 52 indicates rear twin beds. A Model 53 indicates a rear island bed. There used to be a series of models after that that included various bunk and lounge combos, but they didn't last more than a couple years.
Not many of these combos have lasted through the life of Sunline, but the 53 stood out. It was the only one that lasted through the end, other than the 52 which could be custom ordered in more recent years. Sunline eventually stopped designating these twin bed models as 52s, even though I still refer to them that way to distinguish them.
There's only one break in the 50 Series: the 22' bunkhouse uses 50 and 51, but it doesn't refer to rear bedroom layouts.
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