A few thoughts on this:
One benefit to pointing both locations to the home page is that you could actually be helping your Google maps rankings by pointing the listings to the more authoritative page (the HP over a subpage, especially if the location page is new).
However, pointing users to the home page could be confusing as the locations are not even close to proximate.
So, if you make it really easy for users to get the localized information they need once they land on the home page, that might be your best option. (Off the top of my head I'm not sure what that would look like, though, since a two-location business doesn't really merit an "enter your zip code and we'll point you to the right location page" feature).
If you want to give users the best experience when they reach the site, linking to an actual location page is probably better. But you do risk a rankings drop in the maps here. If you're going to take this approach, I suggest building out the location pages and swapping over all of your other directories to the location page first so Googlebot has some time to see those backlinks then make the switch.
Additionally, make sure those location pages provide information users wouldn't otherwise get (localized reviews, events if applicable, directions, anything unique to that specific location).
