Your ideas sound quite lovely. Try painting a large piece of foamcore in each of three paint colors. Tack them up on the house for a few days. If you put them where you can see them as you drive in, and then move them to the entrance you use most often, that'll give you a good idea which you prefer.

By the way, if you are going to have to prime, you can use the traditional white primer for the whole house, then put your paint samples on foamcore up. The samples could look completely different against a background of white primer than they will the current brown paint.