Hi,
I found that my motorhome draws 0.8 amps per hour while not plugged in and the solar is off. This works out to about 35 AH daily when I include the refrigerator (1.2amps when the gas valve is on). This is about what one of my 120 watt solar panels will produce in a average day, considering they are not all 100% pure sunshine.
You can buy a 140 watt solar panel for about $250 at this place.
SunElec.com but check on shipping costs as well.
You can search for a 20 amp PWM controller at this website for about $20.
AliExpress.comI would not worry about the pure sine wave inverter, sure it is "Better" but also 4 times as much money as a 300 watt MSW inverter. Back in 1996 when I bought my Trace 1500 watt inverter/charger, it cost $750 for modified sine wave. A pure sine wave at the time was around $2,250.
Now you can get a 1,800 watt brand name sine wave for a little less than $1,000, and a 500 watt Coleman modified sine wave inverter for $30.
I can deal with the MSW power. Just do not run a laser printer on MSW or a motor. You can run a small fan (nothing that is high torque, and check the motor for overheating after a few minutes). I charge my drill battery, run a laptop, and DVD, TV, satellite system, ect from either my 300 watt inverter, or rarely the 1500 watt inverter (it consumes much more power to get the job done).
Have fun camping!
Fred.