Hi Dave
Solar can be wonderful and has never been cheaper. It just depends on how much power you need, how much room you have to mount it , room to store it if portable and how much sun you get.
We are low power users with basic trailer functions with our biggest draw being the furnace usually at night. We do use LED lights to reduce the load but other than that you would think we had a power cord up with us and we do, it's connected to our 230w solar system. It is way more power than we need but gives us the ability to do more if we want.
You can get 100w kits for around $200 and you could assemble the parts for around the same. The parts for 200w would be a bit less than $400. Unless you are running a inverter a lot, 200w can be a considerable amount.
Our battery is always charged at night fall and barely looses anything over night. When the sun comes up the battery goes into float fairly fast and the panel actually runs the trailer through out the day, The most I have been able to run so far is a 200w 12v coffee maker without affecting the battery.
Speaking of battery, once you know how long your battery/s will last you, you should have enough to last a few days if it gets cloudy. Having a back up plan is also good. We also have a generator that will run our AC if needed and as a last resort we have used jumper cables to charge up the battery before we had anything else.
Our panel is portable and while it's more of a hassle to store and move, it can also be pointed right at the sun all day producing the most power possible. Mounted is easier but you get much less peak time and you have to park in the sun.
Before you buy anything make sure you understand the different panels and the different controllers they use. Smaller panels are usually 12v and use a inexpensive PWM controller. My panel is 24v and is cheaper per watt but the controller has to be MPPT and they are more expensive. Either way the price of the system is close to the same.
Hope it helps