Ape hanger high rise bars will let you sit nicely upright,
But..
You would not want to do any off road single track riding, because all that added length upright , will surely move
with the added leverage of that high rise..
Since I only want to ride for exercise and pleasure I would like to sit up.
given this JRA use , you should be OK..
Adding a Stem Raiser to your fork is another option..
Quill stem type is a Chromoly tube reduced half way of its length, so inside if top is = to outside of the bottom.
you can reuse your stem and bars , if you wish.. inserted in the top..
Maybe BMX bars and a stem ,, that you can get the bars clamped in Really securely tight, will work for both..
You will have to replace all the cables to reach the new height, of coursre
....