There is really no one right answer, and it all depends on your needs, Bill.
Just a couple thoughts of mine. As you have likely seen, there are near as many thought processes as there are owners.
If you aren't reliant on heavy power usage, and do will not be camping off grid for more than a few days, it is unlikely that you even need solar. I went 4 years never really needing solar, camping almost exclusively off the grid, and camped for up to 4 nights at temps just below freezing. I do have the dual 6V batteries. I did just add a 40W portable, wanting to ensure that the voltage did not drop too much in instances like this. It worked great for us last year.
Fixed panels do allow you the ease of not having to set up a portable, for many that alone would be a big factor. Also, it charges while travelling. Setting up my portable panel takes me two minutes tops, and I have really never had the need for more than the vehicle charging while travelling to top up batteries. Another advantage of fixed is storage, and not having to find a place to store a portable setup. I only bring mine along on trips where I know there will be extended off-grid time. With a fixed, you can have all the metering you want built inside the trailer. I guess you could do this too with portable.
Or, as you alluded to Bill, you could have one of each, and have the best of both worlds. A lot of it can come down to cost, and what the setup you choose is worth to you.
There are pluses to the portable units too. Like mentioned, you only need to bring them when needed. You can easily set them up for ideal solar gain, especially if camped under a heavy tree canopy. As well, like Jon alluded to, the angle of the sun much of the year is very low, and a fixed flat panel will not be near as effective. It would also be easier to change out, or add a panel to a portable solution.
So, as mentioned, there is no one correct way to do it. Heck, if I was to buy new now, I would be having to think hard like you are doing to decide which way to go, but for now, no need to hurt me wee brane.