My advice on spiral cut ham is -- don't! But, as you said, somebody else bought it so you have to make the best of the situation. The last couple times I've done it I put it in one of those roasting bags. That helps to keep it from drying out too much. Also heat it low and slow, several hours at 200-225F in the oven until it hits about 140 like Dustin said. The crock pot idea seems pretty good too. I think I'd be tempted to take it off the bone right at the start and then lay the slices in the crock pot. I'd imagine they wouldn't dry out as much since they'd be simmering in their own juices most of the time.
The last few years I've been buying the boneless apple wood smoked ham at Costco. They look a little odd because they split the ham along the length of the bone rather than cutting across it. Imagine you started with a whole ham standing on end and you cut through it straight down alongside the bone. Despite the uncommon shape, these have been the best hams I've ever had. They heat through quicker since it's thinner than a regular ham and the boneless aspect is convenient (unless you were looking forward to making soup with the bone).
A few years back I used the glaze packet that came with the ham. It called for optional inclusion of raisins. I didn't have any raisins but I did have some dried cherries, so I used those. I thought it was excellent. The cherry went extremely well with the ham.