Hi Jayne and welcome to the RVUSA Forum. Any competent locksmith should be able to take a blank key and cut it to fit your lock. Most RV's have RV-specific locksets and you would really have to shade tree engineer a Home Depot lockset to fit. Post back and let us know how it works out.
Reminds me of the story about all the trailers FEMA bought for Katrina victims and then had to have them all rekeyed because "supposedly" there are only about 30 different locks used in all travel trailes..... just like the key for the storage compartments will open about 75% off all trailers storage.... try it sometime.