I'm wondering why you're ending up in Tamaqua in the first place. It's not what I'd call scenic, and the town features a lot of tricky hills (the town's grid plan becomes terrifyingly logical once you've seen the hills). I've been up there a lot because a good friend lives there.
I've driven on 309, and it's a pretty typical PA highway. Narrow, twisty and with drivers who go way the hell too fast because they're mostly locals. Figure cruising speed on a lot of 309 will be 55mph or more. The hills are rather tricky even in a car, so I'd guess grades in the 10-15% range. It's going straight at the hills, so the grades will not be nice. I-81 through there has a bunch of stretches where the grades go above 5%, and PA state highways usually don't mention how bad the grade is... and I-81 is hitting all those hills for minimum climb.
The road signage and numbering around there is pretty bad, even by PA standards. Super confusing. Most stuff is barely signed or just isn't signed, so I have a hard time keeping it straight which road is which. And from the looks of the map, 309 is my usual way out of Tamaqua, which means there are some fun Y intersections where you're dealing with oncoming semi traffic.
If you're used to PA main roads, it is probably ok. It probably would not be my first route pick, and I don't think it's a route most folks in Tamaqua would pick to bike on.