Basically, he is an approx. 16HH QH gelding, aged (18-20), and has gone mostly unused for some months now. Up until 2 years ago he was used regularly as a 'school horse', which involved 2-3 sessions of 3 hour work per week, sometimes more.
I'm only after a horse for trail riding, but I want to know what sort of limits I should expect. What sort of distance should he be able to cover at a walk if I get him into top physical condition? Where I currently have agistment is 11km out of town, and I had originally planned to do some riding in/around town, which I'm unsure about now due to the distance. If I did do that though, he would be kept close to town overnight before being ridden back out the next day, but even so it seems a bit much to expect of him, especially when I'm not exactly light.
I know that endurance horses can handle much longer distances, but he's no endurance horse, so I thought it best to ask.
Also, given his age and lack of recent use, should I stick to say 30min or less walking rides a few times a week to start?