Actually 64 bit enables some additional features on the processor which windows can make use of to be slightly more efficient. Really I don't like supporting reverting back to 32 bit OS's because that keeps us from moving forward as fast since manufacturers have to waste time making 32 bit drivers as well as 64 bit drivers.
For the prince of persia i would definitely go with DOSBox, some old dos games have awkward problems since they didn't anticipate modern hardware so it has the ability to reduce the % of CPU that the game can use, very useful in real time dos games as I installed the old Xcom game and it was like playing in super fast forward till i found that feature, so even if you ran it on a 32 bit system i would still run it inside of DOSBox just for some of its bonus features.
Also, as an engineering major who has dealt with stupid C compilers, i know you probably really like your old ones, but please, please! move on to the newer ones, some of them provide much more useful error messages than the old ones(500+ errors for a missing semi colon on lines 12...), also something like microsoft visual studios C++ gives some nicer programming tools to work with too like providing an actual debugger which would have been the best thing ever when i was being taught C.
Microsoft dropped support for 16 bit programs in 64 bit windows to avoid an emulator on an emulator and because most of the time there is an alternative or better option than sticking with the old 16 bit version, while it is natural to dislike change and want to stick with what you know and are comfortable with, sometimes it takes a bit of a push to get you to try something new which may turn out to be significantly better.