For just power to the gauges, find a fuse that is only hot with the key on, is at least 5 amp rating, and you can get to :bang I recommend using one of the larger fuses, not the minis, they are a royal PITA to hook into.
you can get those cool little add a circuit from your local auto parts store. They are pretty handy. Look in the fuse section. I used the cup holder light hot for my gauge lights.