Built a sales/marketing engine for your bootstrapped SaaS company? How?

Me and my coworkers are trying to launch a new SaaS platform that targets enterprise and MM. Our sales-cycle isn't short and the investment people need to make to use us isn't small.

Has anyone here successfully bootstrapped a company like this without having a personal network of folks that can be early [paying] adopters? If so how'd you do it?

Creating a repeatable GTM motion requires so much trial/error that it feels almost impossible to do it successfully with the runway we've cobbled together from our savings (about 6 months).