A lot of people are struggling to vote for Trump, but for those members not solidly in "Red" states where all the Electoral College votes will go in winner take all contests to Trump and the solidly "Blue" states where they'll go to Clinton you have to decide whether to you "hold your nose" and vote based on the best of bad choices. The "battleground states" make the decision particularly important to vote AGAINST Clinton casting your ballot for the current pragmatic alternative, Trump.
While the Libertarian ticket is far safer on the 2A issues than the other two (No Fly/No Buy advocates), they can't practically defeat Clinton in any of the battleground states and that makes the decision to vote for them much more difficult where the 2A is your primary interest. For the states solidly Red or Blue it becomes a question of which platform you support.
PA being a battleground state that could literally decide the result of the election, voting against Clinton becomes highly important. Voting for a pragmatic alternative to Clinton to prevent Clinton winning the election becomes highly important.
Many voters think Trump can do a lot of harm as POTUS, as can Clinton, but keep in mind that that is moderated by the legislative branch. Our current president and the Antis tried everything in the book in attempts to ban entire classes of firearms, but the House and Senate blocked those efforts. The same can take place on a broad spectrum of issues. Trump will probably have even less support from the House and Senate since he's run an anti establishment campaign and personally attacked a large number of members of the Senate. They'll be unforgiving for this and limit what he might try to accomplish. Since we know the other party has no love for him, he won't get support from them further limiting his impact. Much the same might be said about Clinton, but the spectre of Clinton appointing 3 Supreme Court Justices should make every 2A advocate uneasy about the future of private firearms ownership. There's no way that empty seats on the SCOTUS bench will be tolerated after January and Clinton is clearly far too dangerous to allow to fill those seats with Antis. Any bluster that appointments could be blocked for 4 years is just ridiculous hyperbole.
Understand that the "down-ticket" vote in the Senate is very important as well since legislation that never makes it to the President for signature into law is how we've maintained our rights in this case. It is important to look at who is running in those races and make sure the Senate races go our way to keep whoever is in the Oval Office from having a decision to make.
So, Trump can be moderated more effectively than Clinton by the House and Senate and that may be the hold your nose rationale for voting for Trump in PA.