I replaced all the cargo door locks on our Big Country after others found their doors open and items missing while units were in storage. Went to a local locksmith with one of the locks and he had replacements that were keyed alike, in stock.
The locks I purchased were just over $4 each. Considered going to a barrel type, but locksmith, who has an RV, recommended I save my money. He pointed out that the lock was not the weak point on the door and really the most you can expect is for them to keep people honest. If someone really wants to get into an RV compartment, it would not take much work no matter what type of lock is installed. Just my observations....
I do not have a lock on my propane compartment.....when in storage I do have them chained in with a heavy chain and lock....again, will help to keep people honest.
Travel Safe!