If you're considering a disc brake upgrade, I'd also recommend Performance Trailer Braking.
If you're planning to keep the drum brake system, I'd recommend most anyone but Trekwood. Why? Their shipping will be more than the cost of the axles....
I just upgraded my 5200 pound Lippert axles to 6000 pound Dexter axles, new springs, wet bolt kit, kept the Morryde CRE3000 system and installed Morryde X-Factor cross braces on all three spring hangers.
I bought my axles from
https://thetrailerpartsoutlet.com/ Their prices include shipping and they have a military/veteran discount if you're a veteran. If you want to talk to them about what they can do for you, ask for Sarah Mooney. She's the one that set up my order and was a wealth of knowledge through the entire process.
As for "Keystone using 86.5/68.5 axle measurements, that's pretty much the "Lippert standard for all RV manufacturers".... It's not "just Keystone".....
Since Lippert builds "virtually every conventional welded RV towable frame" it's the same frame and same suspension under a Jayco, a GD, a Forest River or a Keystone.....
A "caution about having a Keystone dealer change out your axles: When I approached three dealerships over the winter when they were looking for work to keep the shop open, they all three jumped at the opportunity to do my trailer. Keystone in Goshen refused to ship 6000 pound axles for installation on my trailer. They said that their "engineering department wouldn't sign off on the modification" so they wouldn't ship the parts. Trying to buy the axles from Dexter at that time was more than double the price of buying them from Trailer Parts Outlet. So, I decided to just do it myself. It's not a technically difficult job, but it is a lot of manual labor and you'll need a helper that can lay on a creeper under the trailer to help "muscle axles into position".....
PS: YES, you really need the 86.5/68.5 measurements. That's the only way you'll be able to keep the springs positioned under the frame rails on the spring hangers and keep the tires in the wheelwells.