No matter which 2004 Volvo wagon you have, they all seem to have a towing limit over 3000 lbs, but check your own owners manual for an exact figure for your vehicle.
And, in all cases they require electric brakes
on the trailer for those over 1500 lbs, but so does CA where you live anyway.
That said, it pretty much covers all of the 13'ers, including the somewhat heavier 13' Scamp
w/front bath, but some 16 & 17' might be a bit on the heavy side, depending on which chassis you have.
Look in the General Discussion forum for a listing of Real World Trailer weights for actual weights of loaded, ready-to-go trailers in different sizes.
Just as a tip, In SoCal good trailers at moderate prices are few and far between, meaning you may have a trip in your future to get your dream trailer. If you see a real bargain, say in Craigslist, odds are it's a scam, Much like the 13' Casita
currently listed in San Diego for about $3000.
Again, if you consider other brands and models it will open up the possibilities considerably.