Putting in the work, but no clients yet. What would you do in my shoes?

Have you thought about partnering with lawn companies?  You could have them send out a discount offer to their clients for your service, and in exchange, you provide them with a referral fee for any client who signs up for your weekly service. 

The nice thing about lawn companies, at least in my area, is that they tend to focus on specific areas to build their clientele (neighborhoods, subdivisions), which reduces travel time between jobs.  I'd imagine the same applies to your business, too.