Setting up my 90’s MTB for local exploring: roads, paths, hills, and camping

I would like to do 5-30 mile day rides and an occasional 1-2 night bikepacking trip. I ride mostly on road and gravel paths, only occasionally something more rugged. There are a lot of hills where I ride.

I have a 90’s hardtail mountain bike and I’m curious about modifying it for this type of riding but I’m not sure that is a worthwhile idea. I’m inspired by this community so I thought I’d share my ideas and ask some questions.

This is a 90’s Giant CADEX ALM-1 (aluminum frame) with a Marzocchi Bomber front suspension (I think it is pretty cool!) and 26” wheels. I bought the bike on Craigslist 10 years ago from a guy that built it up on his own and have pretty much left it as-is except for a few swaps of simple parts that needed replacing eventually, like the seat post and pedals. The frame is apparently 18” but I don’t really know what that means and I am 5’8”

The bike has served me well for casual mountain biking and short urban commutes but I have some problems with it:

• Handlebars and comfort: The seat feels like it is at the proper height relative to the pedals, but when I am riding for a long time or up a hill, my lower back hurts and I feel uncomfortably hunched. I feel like I want the handlebars to be higher (and maybe also angled more towards me). I think the frame might be too small but I’m wondering if I can still make it work. I thought about swapping the handlebar for something taller and more angled? And/or a stem that is taller and farther from me? Does that sound right? Any recommendations?

• Tires and speed: Unsurprisingly, I am slower on my 26” MTB in the city than my friends who are on road and hybrid bikes. Would swapping the large treaded tires for something slimmer and smoother have a meaningful impact on the bike’s speed on roads? I know there are other factors but that feels like maybe an easy one to adjust (I know the suspension plays a role here too – more on that below)

• Suspension and efficiency: my cushy suspension feels pretty inefficient for the type of riding I’m actually doing. Although I do enjoy it at times – it is fun to hop around and be a bit more aggressive in technical situations – I am wondering if I should (could?) replace the front suspension fork with a rigid fork? It doesn’t sound like it is unheard of – it looks like maybe I could swap it with something like a Surly Troll fork? This doesn’t feel like the most pressing issue but I am generally curious what people think. Suspension doesn’t seem to be very popular around here!

I need to figure out some other things, like mounting gear for bikepacking. And I think I should replace the brake and shift cables because it’s been a while and I think the bike can use some love. All of this sounds like fun but I admit I am inexperienced and want to get some feedback before I go too far down a rabbit hole – Thank you!