My girlfriend just moved out here and having somewhat of a difficult time finding good roads/routes in the area (seems like most roads lack shoulders out here). Any suggestions? Rt 126 from Holliston to Hopkinton center is nice, but that's about all I've found on limited research. Suggestions?

Heaps of routes.
Ride with Grace Bicycles in Holliston, look at Mapmyride, pick up road marks.
Check Rubels maps. Google bike map routes by aiming at towns. Most roads are great riding.
Rt 16 is busy and you have to work at getting past Milford but there is the new UCRRT that helps alot. https://www.townofholliston.us/hollistontrails/ There are links to the Milford portion.

Online mapping sites and Rubels are widely touted, but since the 1970's I've just used a Metropolitan Boston AAA road map. I ride from Kenmore Square in all directions and it covers enough area, in enough detail, and is pretty easy to read. I have found numerous routes in all the sectors of the Metro Boston region in loops up to 75 to 100 miles, including the Holliston-Hopkinton area. I find the Rubels maps much harder to read.

One problem germane to this area though is the crazy road patterns, and finding the quietest routes is difficult since I find I always have to stop and pull out the map. My rides to accomplish a certain distance are often time-limited so I don't want to get lost and hence I often skip the smallest roads, though I'm seriously considering a GPS to solve that problem.

On my AA map I have marked off distances of 10, 20, and 30 miles in all directions from Kenmore so I can easily plan a route loop for a specified distance, without tracing a tangle of roads as on Map My Ride.

Jim from Boston,
Well said. That must be some AAA map!
I find Rubel and now Google Bicycle and Walk mapping are resources to find good roads and avoid bad ones. Neither are perfect and sometimes misleading.

I don't take my GPS too often but when I do it gives me confidence to explore new routes or investigate odd places. I bought it hoping to mitigate reading glasses and map folding exercises. I found route planning, navigation within the GPS keyes and software and it's own mapping peculiarities not worth the trouble. Now I wander and pull it out to figure out where I am. The particular brand and vintage routing in my GPS is far worse than Rubel's or Google and only dreams to aspire to your AAA map.

You can sort out routes you like Sunday mornings when there is much less traffic.

I think it was Rt 85 out of Hopkinton that I liked to ride. Then there was another nice road off there that may have headed to Marlborough. It's been a while though so I'm not 100% sure on the names!

There are quite a few nice roads that intersect 135 though. Just depends what kind of mileage she is looking for.

Guy2600, I'm in that area also and I have a few loops that are from 13 up to 35 miles so far. I'm just getting back into it so my loops vary in distance. Rt 85 has already been mentioned, 135 is actually pretty good riding, I haven't had a problem. Rt 30 through southborough/westborough, 140 in grafton/upton.

If you are near the start of the Boston marathon in Hopkinton, here is the 34 mile loop: From the start of the marathon, head west on 135. turn right on 140 and take that all the way to RT 30 east. Here you have a couple options. The route I did I turned on Flanders road and took that all the way back to 135 in Ashland and back up the hill to the start of the marathon again. If you want to extend the loop, continue on 30 to 85 (about 4-5 miles passed Flanders Road) and turn right on 85. From 85 you can take that to flanders road, turn left and take it to 135 or continue straight on 85 to 135 (you would take a left to get back to the marathon start with this option). Continuing on 85 straight will take you passed Hopkinton State Park for a point of reference.

Sidenote: am I using the correct wording of passed vs past in the sentence above, lol?

Good luck and have fun!