We were at Volcano Park in December and the Jager overlook is the best spot to see the lava glow. Imo, the park isn't so far away from even Hilo. We stayed with friends about 20 minutes away from the park.
My other observations were that I thought the food was mediocre and over priced at the Volcano House. At the the park, the night time viewing at Jager Museum is really the main event. Getting to this event to hear the park rangers narrative is a plus.
If you are considering driving to the Jager overlook and waiting until after dark to leave it really isn't a hard drive to the Hilo area. There are many restaurants and things to do here. Not so much at the park.
Another observation is if you stay at a b&b you may experience the real Hawaii. This could be good or bad depending on air conditioning and type of construction the b&b is. The tropical rain forest is really noisy with coqui frogs all night and roosters in the morning.
The best advice I received was wait until you arrive to decide to go to Volcano Park. Its very common for this to be a very rainy trip. We arrived in Kona and checked the weather before deciding to go to Kilauea and Mauna Kea. We had a very clear night at both but the day before Kilauea was a hard rain.
Other Big Island areas that were on our must see list were the Black Sand Beach, Green Sand Beach, South Point and Mauna Kea.
Mauna Kea sunset was great. We had a fairly clear day. We drove to the top in a Dodge Charger and came back to the park for star watching. This was really cool.
Black Sand Beach was ok. Its a beach with black sand.
Green Sand Beach was ok. Its a fun 4x4 trail ride or a two mile walk. Its just a small beach with greenish sand.

The locals run an old 4x4 shuttle here. Im not sure what it costs as our buddy had a Jeep.
South Point cliff. Its a cliff with a jump off into the ocean. Its an easy jump with a metal ladder climb back to the top.
Best beach within 30 minutes of Kona is beach 69.
Our favorite snorkel beach in Kona is Kahaluu Park. The resort, Kona Town and this park is all a person really needs, imo.
Bill