I've had both types of microwave venting and each has its pros and cons. But yes, it is quite possible to vent outside and probably worthwhile if you use it a lot as you do. However, you will get air in through the opening as well, contributing to heating and a/c inefficiency, and if it has a flap type closure it can rattle in the wind.
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL