A tip for finding larger sites: Go without hookups. The cost of utility runs is calculated by the foot, so sites with hookups tend to be smaller and closer together.
If a campground is a complete unknown, we'll usually request a site with no hookups for this reason. Once we're there, we'll look around some and if there are empty sites that are more to our liking, request to move. (Sometimes Google Maps, with the satellite view, can be useful for picking out nicer sites - for instance, ones with more trees. This only works at state and national parks, where reservations are for a specific site. Private campgrounds usually don't do site-specific reservations unless you're a regular.)
In general, all else being equal: State Parks have larger sites than private campgrounds. National Parks have larger sites than State Parks. National Forests and COE campgrounds have larger sites than National Parks. Dispersed sites are the largest of all (duh).
Also in general: Ocean front or lake front, where the ocean or lake is the main attraction, sites tend to be smaller. (Ontario PPs are often an exception to this one.)
This is all a gross over-generalization - there are exceptions to everything - but we've found it to be a useful guideline when visiting a place for the first time.
2021 Four Winds 26B on Chevy 4500
