Sensible.
The S70 and the S60 are very nice sedans. Safe and very roomy, and the best driver's seat in the industry. If you could find an S70 with a manual, wow!
The 1999 -> have an electronic throttle control, no wires. It is prone to failure, but Volvo has agreed to "fix" it for 10 years or 200,000 miles. The timing belt for 1998 needs to be replaced every 70,000 and the transmission fluid needs replacing every 25K.
The worst 2 features in the S70 are the leaking AC evaporator (a $1500 fix) and the vinyl coming loose next to the inside door handle pocket.
I would budget $1500/year for maintenance. You are not parked in a garage, so DIY is not feasible. I would look for cloth seats, parking outside in the sun is death for the leather.
My daughter will have our 854T at school next year. It has a sun shade for the inside of the windshield to protect the dash. I am also contemplating buying a solar powered battery charger - she doesn't drive a lot.
There are a lot of S70 and 850s on the market. Shop around a lot. Make sure the car comes with service records so you do not duplicate and waste money.

Klaus
--
(V♂LV♂s 1995 854T, 1998 V70R)