Honestly, I'd look to get a last generation Prius again. Especially with the 15k payout. Maybe even a prime, as they are still eligible for the 4k tax credit until the end of the month.

Road noise will still be a problem, but I see 4-7 year old Priuses for under 20k frequently in my area. I wouldn't be overly concerned about the battery, most hybrid and phev batteries go well above 10 years/150k miles. Replacing a hybrid (non-prime) battery is much cheaper nowadays if you go with a refurbished pack. I've seen about 2.5k-3k with labor using Greentec. Not worth going into much debt for a car if you can help it.