The Shimano freewheel is a really good choice... they deliver some seriously good bang for the buck.

I usually base my gearing estimates for other people by using a 700:25 wheel as a base... a larger wheel and tyre size will yield a taller gearing while a smaller tyre will reduce the result.

If you are running the small ring off an old road double it is probably a 42... mate that to a 16 tooth freewheel and you will have a gearing of about 70 gear inches which I think is pretty close to ideal for all around riding. If you ran a 52:18 you would get a slightly higher gearing of about 76 gear inches which might be something for flatter terrain or stronger riders.

With ss freewheels your cog size is pretty limited so gearing adjustments need to be done at the crank by changing chain rings.

Here is one more idea... that Suntour freewheel is about as nice as they come and if you reinstall the deraileur you could run that and by adjusting the limit screws be able to make manual gear changes. In this way you could play with different gearings to see what makes you happy.