I can't speak to the parking for Diamonds, but the lot is on the small side. There aren't many options in St Paul and this is one of the better hotels. It was in the process of being refurbished when I was there a few years ago but should be complete now. Refurbished rooms were very nice. There are good dining options within walking distance. If you're doing something at the Xcel, it is a bit far of a walk but doable unless you have small kids. The setup for the happy hour was awful creating extremely long lines.