I don't see anything wrong with your plan. If it works for you, that's all that matters and I think it is do-able.
I do think you might be underestimating how easy it can be to leave the campsite in a B and return after exploring for the day. We have learned to keep in mind as we go about camping in our B, that we may be taking off anytime. This way you keep things put away and minimize the time needed to "unplug and go". We typically have only two chairs , a small table and maybe a grill to put away outside. We only plug into electricity daily, not water and sewer. By keeping the interior "travel-ready", we can pull away in a matter of minutes and set up when we return with equal speed.
Your style may be different, so this may not work for you. But you could give it try with a B only, and add the trailer later if needed. Of course you would want to purchase a B with the proper towing capacity up front.
I think it's also nice to have everything with you on day trips (bathroom, food, etc.), so the SUV and trailer idea doesn't fit my idea of the perfect rig for us.