Looks like an excellent candidate for a road / touring conversion... these early mountain bikes were based heavily on touring bikes so often share similar geometry and parts which lends itself to building them up into a more road and trail oriented bike.

The older bikes often had 28/38/48 crank sets and these are ideal for touring / commuting.

If the bike is a comfortable fit now you will probably find that the stem has too much reach for drops and a shallower drop bar can also help with this.

Most have seen this bike a few times... my '87 Kuwahara Cascade. It is a wonderful machine to ride on the road and is supremely comfortable over very long distances. I used friction bar ends and have a vintage drive set up which I prefer to brifters.



Conversely, my '89-90 Moulden gives me a more upright position but besides spending a good deal of time on the road it is set up for spending a good deal of time off road. It has an 8 speed drive and indexed bar ends (index rear / friction front) which are nicer when you are making faster shifts on the trail and the riding position is better for steep uneven decents. With that being said I have ridden it 100 miles and had no complaints... I do spend a lot of time in those drops because of their higher position.



Finally...my Kuwahara Shasta which is set up with trekking bars. I use this for commuting and utility purposes but it would be as capable a tourer as the Cascade if I wanted it to do that.



Some little pitfalls come with using indexed road shifters with mtb derailleurs... the rear is compatible with Shimano but the pull for front derailleurs is so you can't mix and match mtb / road components.