How do I increase the length of my sessions?
So I've finally finished writing out my solo campaign and I'm starting to play it and I've encountered a problem. It's too short. My sessions go for about an hour usually. I'm enjoying every minute of it, but ideally I'd like to play for 2-3 hours. How can I stretch it out? The system is DND and I'm using some elements of the mythic gm mostly for the simplified chaos factor and occasional random events. This is my first time DMing let alone solo DMing, but I've been a player for over 10 years.
I could increase the roleplay and based off my last session that could probably tack on an extra 30 minutes, but I'm terrible at roleplay and keeping track of more than 3 characters in a scene is proving to be challenging in terms of giving them all distinct personalities and how each NPC would react.
I could crank up the chaos factor, but that makes things more unpredictable especially with the character list. I have the whole story planned out for the most part. One of my trivial NPCs who is around for only like 5 more sessions almost died in combat yesterday and I was stressing how I was going to rewrite them out of the game since they have a vital role in at least the next session. I have back up NPCs for the trivial ones, and luckily they survived, but more chaos means more planning especially for the important NPCs.
I could also play my next session but I was hoping I wouldn't go through them so quickly. I'm on session 5 of 42 already and its only been 2 weeks since I started. Each session is broken down into 1 battle, 3 scenes, 3 choices, 5 skill checks. I'm noticing not every choice or skill check is meaningful but they can add up to 3-5 minutes of play per option. I've been writing this campaign for 1.5 years now and I just don't want to go back to writing for another month or two adding more options. I guess I was thinking I'd also get a year out of playing it, but might only be a few months.
I also notice I'm not spending time describing the scene, people, or environment because I already know what everything looks like as I imagine it. I might try this in my next session.
What do you all do to stretch out your games or do you just accept the length and move on?