I'd say it depends.  Oct-early may our trips to the coast mean including the dehumidifier.  Summer, occasionally it is needed.  My advice,  Many of the places you are likely to camp near will have a Fred Meyer, Lowes, Home depot nearby.  You could just wait and see what the weather is like and if you decide you need one, stop in a get a small compressor driven dehumidifier around $100.  When it is humid ours will pull about 5 gallons out the first 12ish hours,  then drop down to 1-2 gallons/day.