I checked his Conservative Union score just to see if there is a correlation. His 2017 score was 84% along with Rubio, Crapo, Risch, and Moran. What is remarkable is Flake got a 92% rating, up from last year's rating of 79%. If you look at those ratings, there are 5 groups at the top. Toomey is in the 5th group from the top. Toomey is actually down in the 2017 rating from 96% in 2016. For Pennsylvania, he is pretty good.
If you looked at McCain's rating of 57%, then you have something. It would be interesting to see Toomey's score for 2018.
Someone who is an open-borders advocate, for example, might get higher "conservative" rating than someone who wants to restrict immigration.
The same goes for defense spending. I don't think there's anything conservative about pissing away hundreds of billions of dollars on a U.S. military that hasn't been operating under constitutional constraints in decades.