Local trailer shop hands down.
I just purchased a 2018 Jay Flight 195RB. It had hardly any ground clearance.
We took it to a trailer shop and replaced the 3,500 lbs axle with a 5,200 with new straps and bolts. We also had them "flip" the axle and put 15" wheels with load rating 'E' tires.
It's important to us to be able to go off road a bit and not bottom out our tanks or snap our drain cap off.
We are well happy with it