Long story short, I have a shorelander single axle trailer (don't have the model #) that has a tendancy to wear the inside edge on one of my tires. The other side is fine. I will be replacing both tires in a couple weeks. Would you guys have the trailer aligned? Alignment was done about 7 years ago, but I trailer a lot on some pretty rough roads.

If you've got a competent frame shop, that can "adjust" the axle so it is in alignment, then certainly do so. But, I've had great luck with Shorelandr parts, and have even bought a new axle from them. I'd get the model & serial numbers, and give them a call. A new replacement axle might be more cost effective.
HRG

I would have a alignment shop look at it. You may have other issues a new axle wont solve.

Jiffy,
It sounds to me like you have one side of your axle bent up. If so, it was most likely caused by hitting a pothole.

If you have an alignment shop check and find it bent, either have it straightened or get a new axle.

The problem with straightening the axle is that it is likely to happen again.

If the axle bent once, it would likely make sense to replace the axle with one that has a heavier load rating.

Double check your fully loaded rig and see how close you are to the load rating of the axle. If you are close, it would make sense to install a stiffer and heavier axle.

Good luck
REW

I'm withn REW.
It is very easy to bend the axles a little. Potholes, etc.
An old fashioned alignment shop can bend it back.
Here in MT it is common. We have a lot of gravel.

Another thought might be to check the axle carrier that bolts to the frame. I had a tire wear problem on a shorelandr this summer . While checking into it I noticed a crack in the carrier = the piece that holds the axle for adjustment on the frame. I ordered a new one from a dealer (under $50) and was good to go! The tire wear tipped me off to what could have been a bigger disaster if the carrier had let loose. Good luck...