You can have a great trip on-site or off. If your savings are substantial, stay offsite and use smart strategies to experience the attractions you want.
In every park, there’s probably only 1 or maybe 2 rides you won’t be able to get at 30 days. So plan to rope drop them, hop in line just before closing, or grab a snack and a charged phone with a movie or game and have some downtime while you wait for that one attraction.
Also, think about your must-do attractions. Are you really excited for SDD or do you just want a FP for it because you know those are hard to get and you don’t want to miss out?
When I think about choices, I ask myself, “is experienceX worth $Y?” So if staying offsite will save you, for example, $300, and you’re tempted by on-site so you can ride SDD and FoP the question becomes, “is a short line to ride SDD and FoP worth $300?” For some people the answer is a hell no, and for others it’s a resounding yes.