Definitely get a bike computer with a cadence monitor. I had one on my 1st bike for about a year, and then lost it and haven't had one for many years. But I know what 80-90 feels like. If I was spinning 60, my legs would be laboring, it would be time to downshift. Anything over 100 feels out of control. This doesn't count going uphills if you only have 2 gears to choose from on the front, you are going to have to do the best you can there. On flats and downhills, aim for 80-90. I have a triple up front, so I still maintain 80-90 if I can, but I was working on some hills in Arkansas last month where that just wasn't possible. I was hitting 5-6 mph uphill on those, and about 30 mph downhill. BTW, depending on the hill 5-8 mph isn't bad. How fast are you getting on the downhills?

As far as time goes, I wouldn't compare your time with others, but I would keep a journal, recording your stats. I like to look at average speed too. Sounds like you have some fun hills to contend with, but the upside of this is that with practice you are going to turn into a great climber, which is what I wish I was better at.