I agree that Libertarians usually hold social views that most freepers would find objectionable.
I disagree that true Libertarians are like big government conservatives. Libertarians believe in personal freedom above all else. Bigger government restricts freedom. Even the most socially indifferent, hedonistic Libertarian sees big government as restrictive.
The common ground that can be built is economics and taxation. Libertarians want free markets and low taxation. With some caveats, we want that too. Libertarians are pro 2nd Amendment. We are too. On social issues, we should push the 10th Amendment and states’ rights. Libertarians on the national level would be ok with that. On the local level, depending on the state, there will be problems with that. Nothing is perfect. We can make common cause on non social issues for sure.
If I have the choice between someone that wants me to change my life because God wants me to (or their interpretation of God wants me to), and someone that wants me to change my life because Big Government demands that I do so, it’s a very difficult decision on which one is more objectional to me. I’ll pick third party each time. I agree with conservatives on pro-gun, free market economy, religious freedom (especially in regards to ACA), lower taxes, and less regulation. I agree with dems being pro-choice, pro-gay rights, ect.
So find a way to reconcile that, and I’ll put more than a few toes into your big tent. Might even vote on your side, instead of third party.