I had a 2011 KZ Escape E14RB, basically the same floor plan as the 130 you're looking at. Mine came with a lower-mounted axle and 14" tires. Even at that I had a blowout in year 3. :( I note that KZ lists an Off Road Package, with 15" tires and extra ground clearance; is that available on the 130RB? If so, you could factory-order one. Or flip the axle and add larger rims & tires, like MFL said; some Sportsmen Classic owners were doing this (I was on a KZ forum at the time). Definitely worth having more tire capacity; 674 lbs is not a lot, especially if you fill the hot water heater and the fresh tank... that's 215 lbs right there.
A boxy trailer like the KZ took my fuel economy down to about 3 mpg less than the fiberglass egg trailer (Burro) I previously owned. It makes a difference in performance, especially if you hit a strong headwind at altitude. Do you have the 4-cyl or the 6? The 4 will do, sort of, if you stay out of the mountains. But the 6 would be better. A Scamp or Casita will tow more easily. To hit your price point with an "egg" you'd be looking at maybe 8-12 year old trailers. I assume you're aware of
molded FG trailers for sale site?