Your difficulty will have nothing to do with where you are staying. Some beach lots fill up early and if you don't get there early then you are out of luck. Beachcomber Restaurant charges $15 but gives you a $15 coupon for food/drinks. These lots do fill up so arriving early is important. Not sure about the ponds needing a pass but do not believe they do.
I think that you do need a permit for the ponds the same as the bay or ocean beaches. Please refer to this website for more info:
Does this mean that there is literally no place to park? or can I find someplace that's less convenient?
Check current requirements, but from past years, stickers were required at all the ponds and Bay beaches except for Mayo Beach. You can pay a daily fee to park at Cahoon Hollow (or park at the Beachcomber, see above), and at White Crest. The others are accessible without a sticker after 4 or 5 in the afternoon. There is no nearby alternative parking at the sticker beaches, though you could ride bikes. Parking is prohibited along the roads near the beaches.
Truro has lovely beaches. Why don't you just buy a sticker to go to those beaches? Actually my favorite ocean beach is in Truro.
While I realize that Wellfleet's beaches are lovely, they are really just an extension of the great outer beach of the National Seashore that stretches from Orlean's Nauset Beach to Eastham's Coast Guard and Nauset Lighthouse Beaches all the way to Provicetown's Race Point beach. So if you are staying in Truro, go to Truro beaches, if staying in Eastham, go to Eastham beaches.....no problem as long as you buy the National Seashore pass or bike in.
Okay so....you are on the Cape in high season is that correct? Neslaw mentioned the free parking at www.thebeachcomber.com. The website does not state it but what he says is accurate or at least was for years through last summer. There is a small city lot there in between the restaurant (a former lifesaving station btw) and the top of the tall dune. You will see this in the pictures of the Beachcomber. But behind the restaurant they have lots of parking. You will still need to arrive by 11AM if you are there in July/Aug. There will be a line but don't worry, that is only there because the are not yet open or are just starting to process the cars. You can also come when folks begin leaving after 2PM.
Once you get your car securely parked enjoy the gorgeous beach there at Cahoon Hollow and come back up the dune when you get hungry and spend your parking voucher on a variety of food items.
Oh and since Yellowbird mentions the Nat. Seashore Beaches and stickers....if anyone in your party is 62+ then you can buy a one time - forever parking pass for $10.
do you bike? there are lots which are a ways down Cahoon Hollow and many people park there and bike the 3/4 mile (estimating) to the beach entrance (or just walk) and if you pass the beach and make a left then there are ponds and there is always room for a bike.
@CCC I checked the Beachcomber website and that information is still there.