In a situation like this, I would turn to your Google My Business page and make sure that the locations or distance that you serve is set properly in order to reach all of the surrounding towns that you do, in fact, serve. It doesn't necessarily hurt to include your small town name in the meta title. While that will help with more immediate local traffic, Google does change titles and descriptions in the SERPs for certain terms they feel the page is relevant for but do not feel your other info adequately expresses. Google will take into account the location of your business but if your GMB page shows that you service a nearby area, they won't just discount you because you're in nearby small town instead of Big Town. In cases like that, you may find that Google alters the page title in the SERPs to show the name of the bigger town or completely remove mention of any town. So just because your title and description don't perfectly reflect every single area you might work in, that doesn't mean you can't show up for those local searchers.
It can also be useful to make pages on your site specifically talking about the services available to those bigger surrounding towns. So even if your homepage is more targeted to Small Town, you can have an organic landing page devoted to Big Town A and Big Town B with all your info, service information, a blurb about the town and how your business interacts with that area, and a nice call to action and/or contact form for that town. Just make sure not to copy/paste to create tons of targeted pages like that. You want everything to be nice and unique so there are no duplication issues.