Vacation woes

I really thought I was being clever when I realized that it might be a good idea to make reservations for our summer vacation this early in February. Much to my chagrin when I hopped on the internet to Farragut State park in Idaho (which is minutes away from Silverwood amusement park which happens to be the kids favorite part of the trip) and I started looking around expecting to find a plethora of options... I was wrong. Dead wrong. There is nothing left for the week Shane has off. We've been doing this for a few years now and I thought this far in advance  from July I was really planning ahead, but apparently other people plan better than me. So now we are trying to figure out what we can do. We have a trailer that we are still paying on and want to use it so we are looking into splitting up RV spots, or coming up with Plan B or maybe Plan C... The Ocean, the forest... anywhere just not the desert. We have over a week to fill with family time and I feel defeated because my brain can't come up with another idea. Yes we have time but obviously things go quickly. Help!