I recall a trip in a Viscount in 1972 from Salisbury (Rhodesia as was) to JNB. The machine could not climb above the thunderstorm and too far a diversion - so we went through a large part of it at 16,000. Not very comfortable. Overall, the Viscount was wonderful and the last time I was on one was probably 1986 or 87 on the LHR-IOM route before the 146 entered service.
I've been on about a dozen turbo prop types and found them all pretty reasonable (other than a Saab 340 over the winter mountains of Austria!) and agree that one should sit towards the back. My last was an ATR for BHX-IOM in 2017. Just take your noise cancelling headphones - even if you don't play any music - just have them on to muffle the sound.