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Funny, my Prius needs some front end work too, when I was changing the oil when I first got it, the driver's side front wheel had slop in both directions. I didn't confirm it but pretty sure wheel bearing in my case. It makes no noise at all, but the slop is more than it should be.
I have my hitch installed and I see an mpg drop, but I have the plastic cover in the back off still. In limited testing I'm seeing around 5% effect with panel off + hitch.
One thing that would be a good idea to check on is the inverter coolant pump. You can see it right behind the driver's headlight. With the car in ready mode the pump should be running and if you can get a finger on the hose you can feel it running, or open the reservoir and check for fluid flow. Mine was completely dead, worked fine for quite a while, but with the lower block and driving a bit faster than normal it tripped off on a trip to a near by city P0A93 was the code for it and it seems to only flag when the inverter is overheating (the metal below the top cover is a good place to feel how warm it is. If it feels hot, it's over heating, warm is ok, I think the normal temp was something like 120F, when mine set the code it felt just below scolding temp, maybe 160F ish).
On the AC pump, it might be mainly the logic used to control it that's killing the mpg. Electric motors and AC systems generally don't change too much for efficiency. Like "window shakers" run around a CEER (combined energy efficiency ratio) of around 10-12. The ratio is btu of cooling vs watts used. 12,000 btu that uses 1200w is a rating of 10. My old ac unit from 1990 was around 8 and the new one I just bought is 11.4.... 29.8% less energy used for the same cooling, but that's jumping over 30 years in tech in one leap, R22 vs R32 and such, not even the same refrigerant lol.
In the stores I saw a ranting range of around 10-11.4. I'm sure car AC systems will be all over the place since it's not a simple packaged setup, same pump design is probably used on several models of cars and such.
I actually went on a trip running AC at higher speeds and the mpg effect wasn't too bad, but the faster speeds was a huge hit lol. Around 45mpg going 72mph with AC on. Trip home at around 60mph and 55mph back roads I hit around 50mpg with AC on. It wasn't a super hot day, but I had passengers. I sure do like the 60-65mpg trips at 40mph better with ac off lol.
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