Generally speaking, up to the lower 30s won't be too much of an issue at most SPs & NPs. Once you go past the mid 30s length the possible sites available for a longer rig drop rapidly.
What gets really frustrating is arriving at pick your own site CG to find the few sites able to accomodate a larger rig being used by a class B or a C that could have easily fitted in another shorter site nearby. Get used to it.
If you are a weekend warrior you will get to know the parks you frequent the most & adjust to suit. If you are a traveller never returning to the same park, not so easy.