We have a lot of teams using HelpSite.io [1] for this sort of thing. Originally designed for customer-facing FAQs, we also support the same format for internal knowledge bases. We didn't originally intend to support such use cases, but it turned out a lot of people really like our format for internal company docs as well.
- Keep your product really simple. The more complex it is, the more you need to teach and sell. If your product does one thing well and can communicate its value clearly on a homepage, it requires a lot less work from you.
- Tactically: you don't need to respond to emails M-F 9-5. Yes, that's when many B2B customers are working, but they don't know what timezone you are in, and it's not uncommon to have a delay in answering emails. Just be sure to answer emails before work and after work.
- Create lots of FAQs (using https://helpsite.io – shameless plug) so you aren't answering the same questions over and over.
- (Actually you'll still have to answer many of those questions, but at least you'll have a quick link you can send them)
- Focus more on inbound marketing (creating blog posts, SEO, AdWords, etc.) rather than outbound sales, which requires a much higher amount of active work that you can't do with a full-time job.
For people who value full control and self hosting, Raneto looks like a good starting point to build from.
After having had to build knowledge bases in each company I worked in or go through the pain of implementing something bloated like Zendesk, I built a SaaS version of what I really wanted: the simplest knowledge base out there that stays out of your way.
The cost of SaaS apps can really start to add up. What's interesting is that there's a very similar "stack" that almost all SaaS apps need to buy from other SaaS apps, and many of them don't have a free alternative.
There exists a whole class of apps/services that could gain a lot of traction by providing a freemium model. By becoming one of the best solutions AND having a free version (for limited use), I think you have a better shot of becoming part of a new bootstrapped SaaS business' "default stack".
This is why we gave HelpSite.io [1] a free version that includes features that I consider "necessary" for any business no matter how small, even when most of our competitors are charging for some of them. The more you can align with a startup's own business model (e.g. they need lots of light services up front even when they have no revenue; later they will have revenue and use those services more heavily) the better off you will do.
[1] https://helpsite.io