will a group 24 and a 50watt panel be enough for 2 week trip

FYI. Canyon Village, Grant & Fishing Bridge have showers. Two shower tickets per day are included with the camping fee at Canyon Village (don't know about the others.) Before vehicles went electronic I would start my truck, swap batteries with the trailer and then run on the trailer battery for the day, recharging it. Now I'd make a 12v power & ground only trailer plug so I could connect my 7-way to the battery (but disconnect it each time I stopped).