I was told it was Laminitis (X-Rays showed no rotation). He was taken off feed and then on 99% stall rest for 8 weeks.
Of course vets can make mistakes, but laminitis is also very common & often 'sub clinical' & not recognised. What was going on, that the vet decided it was laminitis? Is/was he overweight? What was/is he fed? Why was he on 'stall rest' for 8 weeks?? Was he so sore he couldn't walk outside??
or because it was so mild a case, he bounced back quickly? I was told I can't trailer him or ride him until next spring??
Certainly could be the case. The thing is, laminitis is so common, but most cases of laminitis start out 'mild' and go unnoticed, until/unless it has progressed to a real, full blown problem, often with mechanical changes, such as 'rotation'. By that stage, some serious rehab is usually needed. But if the 'mild' signs are heeded, it shouldn't generally become a big issue at all.
Re trailering & riding, yes, these can both be a big problem for laminitics/lame horses. But without further information, I'd just say listen carefully to the horse & be considerate of him & he'll tell you what he's up to.
What treatment has the horse had(aside from being cooped up)? What made the vet say so long locked up & not ridden/trailered?(I'm guessing it's not Spring now, where you are). What has your farrier said/advised/done?