My guess is that all reservations for both Goblin Valley and Capitol Reef (Fruita) would all be booked for that weekend as well. However, there are other possibilities near Capitol Reef. There are a number of other campgrounds up on Boulder Mountain such as Single Tree and Pleasant Creek that may still have some open sites.
Memorial Day weekend is one of the most popular weekends for camping here in Utah, so just about all campgrounds, especially those near popular parks, state and national, will all be booked by now, leaving only the "first come first serve" sites and primitive off road sites available. And even all the primitive sites will get filled in a hurry that weekend.
I've learned that when I want to take my family camping over a peak weekend, which are generally around holidays, is that I must make reservations months in advance, or take an extra day of work off to try and secure a "first come first serve" site before others move in.
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