Yes, the lift kit at least used to be available from the factory. If you can get it from them, that's the easiest way to do it -- it's just 2" square tubing, but it's cut to size, the holes to mount it in between the axle and frame are pre-drilled, and it comes with hardened fasteners. If you can't get it from the factory, you can still do it, but will just have to do the cutting and drilling yourself.
Before you get too far into this, take a close look around every side of your current tire to see how much clearance you have now. Look up the factory specs on your current tire, and see how the tire dimensions compare to the dimensions of the new tire you want to get. TM's are pretty much made by hand, and so it's not unusual for every unit to be slightly different here or there due to manufacturing variances. In going from a 14" to 15" tire, the radius increases by 1/2", so you're not talking about a huge increase in physical size, but you want to make sure you have room before you install. Don't forget to compare tire width (width of tread).
Also, when you have the wheels off, it would be an excellent time to change the brakes, especially if you don't think they've ever been done before, and especially considering you have a somewhat smaller TV (compared to say, an F-250). If your husband has confidence in installing the lift kit, then he will probably feel confident in changing the brakes -- they are far easier to do than brakes on the car, especially if you buy the whole kit. And buying the kit is literally only a few bucks more than just replacing the pads and magnets, which is the minimum of what you'd want to do anyway. You may also have to get new drums, since I have never been able to find a shop to turn the armature surface (the surface on which the magnet rubs).
And if you're replacing the brakes, I think I would probably get the self-adjusting ones. They're not much more expensive than the regular ones (I think about $50/side, which is about $15 more per side), and folks here report they work well in maintaining braking power, unlike the regular ones whose power fades over time due to lack of user maintenance.
And since you'll have the drum off, I'd inspect and repack those bearings if you don't know if it hasn't been done in the past few years.
As far as cost goes, my post-it note estimates are:
- $150 = 3 new rims x $50/ea
- $400 = cost of 3 new 15" tires, balanced and mounted
- $50 = lift kit
$600 = cost of new tires
- $100 = new self-adjusting brakes, 2 at $50/ea
- $100 = new Dexter brake drums, 2 at $50/ea (I believe they come with new bearings, but double check)
- $5 = new bearing seals, 2 at $2.50/ea
- $5 = wheel bearing grease
$210 = cost of new brakes, drums, and I think bearings
$810 = $600 + $210, total running gear rebuild, excluding labor. Call it $900 even.
Certainly you are upgrading components of the trailer from what the factory installed, but the bulk of the $900 cost is simply maintenance on a 14-year old trailer. Half of it is just the tires alone (excluding rims). And after you do it, I would feel quite confident, as I do with my trailer, that it's likely you will never have a blow out, and your stopping power will likely be much improved, which is not only obviously a huge safety factor, but a big stress reliever too.
Dave