Let me just say I recently purchased a 2001 Honda Insight CVT with 105K miles. It also ended up needing a new IMA battery, but that was not something I initially budgeted for. I paid way more than $2000 for the car, too. Just do the math on all the necessary repairs. If I had to do it again, I would absolutely run away full speed from the specific vehicle I bought. I will never recoupe the repair costs in gas savings. I would have been better served to buy a 2009 Honda Fit that was in working order. However, that is my specific vehicle which had not been well maintained. In general, if you can deal with a 2-seater hatchback, you may well want to buy that Insight.
Note the CVTs get MUCH lower fuel economy than manual transmissions.
FYI I looked into DIY IMA repair/replace that you will see suggested by Jamesqf and others on the insight forums. Looked like terrible ideas involving many many weekends of research and work, building custom racks to lift the heavy/awkward battery out of the car, home grown grid chargers, lots of warnings about electrocuting yourself to death, etc.
If your hobby is car tinkering with some seriousness and you ENJOY these projects, by all means, read up (a LOT) and then maybe go for it. But if you think this is a good project for a DIY job purely to save money, think again. This is a hopefully once in a lifetime repair. Instead of training yourself to replace Honda Insight IMA batteries, you could spend that time learning to alter clothes and reap a lifetime of rewards.
NOTE NOTE NOTE: The battery packs are problematic. Honda settled a class action lawsuit and had to replace most of them. They are expensive and unusual. Just be aware of this when you buy this car. The battery costs more than the entire price of the car in your case. You will get at most a 1 year warranty (or you can pay like $250 for a 3-year warranty) on your new battery. How happy would you be spending another $2400 to replace it again 4 or 5 years down the road?
WRT to driving without an IMA. You could do the 100 mile trip with some caution. The concern is eventually the lead battery will lose its charge entirely, but if you are willing to drive slowly in the slow lane with your flashers on for this one trip to get it to a repair shop, you could go for it. It will work, but the engine is 67 hp and will struggle on any hills. If you have serious uphill grade to deal with, you might want to just get it towed.