Traps and poison are often necessary inside the RV. Spring loaded traps are very effective but require maintenance. Add fresh cheese or peanut butter to the traps on a weekly basis. Also, check the traps often to prevent dead mice from decomposing in the RV. Poison is very effective but requires careful use. Do not use poison while you inhabit the RV, or if children or animals are present, but consider it when the RV is being placed in long term storage.