Nick,
Jay has given some good info. Unless we get a ton of rain, the flows shouldn't be too high. Late September gets close to the time when they are dumping the lakes out for the winter and you can never predict what's going to come out of a tailwater. Don't worry about being able to provide a truck or having a boat. Plenty of places to wade fish. Some guys may have extra kayaks, canoes or pontoons available for you to borrow. If you rent a kayak or split a canoe with one of the other guys, that will work too. You'd have access to 20+ miles of water with just a PA license. If flows make one or more river unfishable, you may be forced to get a 1-2 day NY license so that we can run to one of the other rivers. I think they are around $15.
If you check the USGS website for flows, here's a good measuring stick for you to use:
West Branch flows between 200 - 800 cfs offer great to good wading conditions. Main Delaware River flows between 900 - 2000 cfs will offer great to good wading levels. Last year it was around 1500 cfs in Lordville and we could walk all over the river without much worry. Helpful tip: If you are over your wading belt and it looks really deep right in front of you... it is. The main stem and WB have some deep holes but the EB has some REALLY deep water. The main river and WB flow at an easy gradient without a lot of heavy water. In some areas the bottom is small cobbles or river rock and silt. Some places have bigger rocks or rip/rap that makes getting around a little trickier. In general, pretty easy wading. The EB is 2 very different rivers. The upper section is almost like a spring creek with many access points. Gentle grade and only 1 or 2 riffs to nymph. The lower section is riffs, runs and long deep flats. Much faster / deeper water. Wading access on the lower section is limited and floating is a far better option.
**IMPORTANT** In NY, the landower owns the stream bottom. Wading or parking your boat where there isn't an easment would constitue trespassing. I found this out this spring when an irate landowner yelled at me. This is really only an issue on the lower EB. There are 2 sections on the upper EB that you can't wade unless you sign waivers from the landowners. To the best of my knowledge, the main river and WB will use the PA law of wading inside the high water mark. I will have access maps for the EB to let you know where you can and can not wade or park your boat.