questions about summer heat southeast tx & full timing

Since window, (and I assume vent/skylight) covers are already done, shade has been addressed, there are two other items that come to mind,,,,,
Instead of an innefficient window unit, add a mini split unit, more efficient and no huge window opening needed.
Also add a water spray to the rv, wet the roof down with a hose two or three times a day, running water until it comes off the roof cool instead of hot. There are automatic sprinkler controls that may be used. hose timer