Yeah, sure, if you're confident you don't need to return the cask to the original supplier :whistle:
Your biggest hurdle will be proper cleaning due to not being able to get your hands or other tools inside.
Most breweries will do a caustic rinse but you'll be able to do a pretty good job with more common homebrew stuff e.g. hot water, PBW and a final StarSan rinse. Use a torch in the hole for the keystone then look inside where the shive would go to check for any gunk.
What style of beer are you planning?
You could probably get away with no priming at all, just fill her up 1-2 points before final gravity and store somewhere ~12ÃÅ¡c for a week.
Then tap, and enjoy. You'll need to be quick though, a typical beer engine setup will suck air in to the cask when you serve so don't expect it to keep well for more than a week.