You are not alone. The same weekend happens to be the start of our 4 month trip. We also do not like to book months in advance however this year we were shocked to find the SP that is our beginning goto & never full CG almost full as of a few weeks ago. It is full over the weekend now, at least for the loop with power. No doubt there is plenty of space in the dry loop.
Luckily we have known events to attend most weekends so reservations can be made but Sunday to Thursday for the most part we will wing it as usual.