I've never looked into a long term rental but I'd imagine that it would be pretty costly. Might be worth considering the purchase of a clean older cart to use for the 3 months then sell at the end. We purchased a '13 cart the other year. It looked to be clean and well maintained and is still looking good. They pop up here in TOV often enough but I think you'd need to be quick.
And then you can get the insurance for it.