Yes, you can fish the river whenever you like.. There's a sign at the end of the park (confluence with river) that designates what is and isn't "the Park", but it's pretty obvious.
Lodging? Sand Springs is RIGHT there, so that is a time honored suggestion, but they're all about the same, I spose.
Yes, they are light biters, these smallies that aren't there.. Yes, I fish by feel, yes I fish the bottom, yes I catch more rocks than fish.. Sure, you can use split shot instead.
And, for the record, I am a fly fishing hack, I usually have my ultralight and a jig out by noon, if not before..