New owner of '05 with only 200 miles

I just got done checking all the connections around the battery, the disconnect was seated and latched with the handle pushed down, I removed it and reinstalled it several times to be sure its fully seated. I went so far as to uncover the battery as in the vid, I removed the service plate to get at the main terminals and I have 214.42 volts at the battery. The 12v battery reads 12.47 volts sitting here disconnected.

What is the spec voltage for the HV battery while I'm here?
I did get almost half a turn on the one lug of the main battery cable from the service disconnect connector, it wasn't 'loose' but it wasn't tight if you know what I mean. That one lug is slightly discolored but not damaged or corroded. (and yes, I wore linesman gloves).
In fact, several of the bolts that hold the battery down to the floor were loose, a few were almost completely removed or never tightened and I found about 7 or 8 extras laying about down below the seat area. To my knowledge its never been apart before unless it had issues when new under warranty and the dealer had the thing out but a history search didn't turn up any past repairs both at the dealer or at Carfax.

With everything hooked up, with the car running, there is still only one blue bar showing at the bottom of the gauge.
Can I put a volt meter on the rear battery terminals that I can read while under load or will that mess something up?
What is the perfect standing voltage in one of these batteries in a perfect battery?

 

I made up a set of long leads with clips for my Fluke meter so I can monitor voltage at the HV battery with the meter on the front seat. I took the car for another slow EV only drive around the block and then some and the volts don't drop much at all, but the engine took over this time after the third mile of slow driving. With the engine running, I upped the pace and ran the car around town and for a 10 mile run down some long back roads where I knew I could give it some coasting time downhill, when the arrow reverses, the volts climb drastically and settle at around 240 while the engine is running and the car is coasting with my foot off the gas. The HV battery volts after sitting for about 20 minutes is now at 220.16v. It seems to be staying there after sitting a while. When I drove the car this time I left the a/c off but had the lights on for most of the drive.

I mentioned that I'd like to talk to someone from Toyota about this to the local dealer and they said I'd need to take it up with the selling dealer, who is over 100 miles away.

What goes wrong with a NiMh battery when it sits? Apparently the battery didn't go completely dead, as it was able to start and drive the car once I replaced the 12v battery. What gets me though is that even though the battery volts climb after a longer drive, I see the same single bar at the bottom of the indicator.
Also, everyone keeps saying that bar should be purple, it looks white or light green to me? I'm a bit color challenged but not completely color blind but I can usually tell the difference between green and purple. The screen looks sort of tricolored to me, its not a full on color display. It reminds me of those old black and white movies that were colorized. The single bar I'm seeing is sort of blue/green and at the bottom of the scale.

 

Both other vehicles are trucks, one is a 1400 mile 2002 Escalade EXT and a 80's F150 with 12300 miles. I'm trying to buy an 88 4Runner with 3000 miles on it from the estate as well. It and a 4x4 Subaru were left to someone who was already deceased. Its not yet been started and it seems as clean as the Prius. He decided who got what vehicles, our names were put on the titles long ago. He may well have known who he was going to leave them too when he bought them. The lot of vehicles is getting split up between about 18 people. We were called and notified by an attorney about the vehicles and what he planned to do about two months before he passed. He wanted to give away all the cars and personal items before he passed so there could be no way to contest the will and no bickering between relatives as to who got what. He had no kids of his own so he divided everything up among the rest of the family. The odd part is its not really like we inherited something of his because he never really drove or spent any time in these cars. They were mostly just spur of the moment purchases that he kept and preserved. He bought cars like they were going out of style, often for no rhyme or reason.
I really didn't want the Prius but neither did anyone else. I have two good cars and a reliable truck already that I had no plans of replacing anytime soon but I guess I'll have to reconsider that thought now.

 

Most of the driving the car will see around here will be low speed around town.
The A/C has been on most of the time so far with the exception of the last two nights when it got pretty cool outside.
The car is black so the sun heats it up pretty fast.

I put the interior back in the car, the battery volts are up to 222.03 after a full day of driving.

I put just shy of 200 miles on the car today, making the total on the car now 479 miles. The battery bar stayed the same all day but after parking the car in the driveway here and then going back outside to move it in the garage, the battery bar was showing three bars. Most of todays driving was at highway speeds, with the a/c off. The MPG indicator was hovering around 49.5 mpg for most of the day.
How far should one of these go on a full tank of fuel on average? After 365 or so miles on this tank of gas the gauge is reading just under 1/2 tank according to the gauge, (three bars showing).
The car drove fine all day, I kept the speed at or near 65mph tops. The car actually feels pretty good, its got more get up and go than I expected one of these to have. It does feel pretty light though in and around truck traffic on the highway.

If the battery is OK, how many miles of normal highway driving should it take to bring the battery back up to normal?
It really seems like they should have given owners a way to plug the car in overnight to either charge or maintain the battery.