FYI, the park hotline is the most reliable information out there as park rangers constantly scour the area. Although I cannot say that I've been up to the park lately, I can tell you that very nice updated information can always be found here:
http://hvo.wr.usgs.gov/kilauea/update/
If the park rangers are saying it'll take four hours for a good peak at the flows, then it most likely will. It will not take 10 hours to get to the VNP from Kona, although I don't quite think that's what you meant.
The paths vary in the parks. Most of the paths are laid out. You probably don't want to venture off into unchartered territory out there because you just might fall in through shaky ground. Be aware of the two types of lava (pahoehoe and a'a) and which one is more dnagerous of the two.
Also, your list of "equipment" sounds good, but just as a safety precaution, make sure to take a cell phone and be cautious out on the roads in the park as there have been many fatalities on the roads there in the past (Pele?).
Aloha