My LDR is an almost 8 hour drive and its working for me. It can work and it depends upon what each wants to get out of the relationship.
I'm not looking to get married, as I'd lose my Survivor Benefit. I am not willing to move... I got a business. He's not willing to sell and move either. We each have a different lifestyle.
We are each able to escape the daily work chores and visit each other for a week or 2 or 3 at a time. Because I am City, he drives and visits me more in the winter. He is rural, so I drive there spring/summer/fall..
Yea, sometimes we go for 3-4 weeks without seeing each other,.. but then he gets so lonely and in the truck he gets.. I get sick of working and jump in my car.. so again, for us, its working so far.
Its been 2 years now and it takes a long time to get to know someone (habits, values, etc.) in this manner. I know I am stuck in this lifestyle for at least another year and after that circumstances may change and who knows..longer stays with him at his place. but its always nice to come home..

Proud of you
Most women just want to wake up, open the door opposite them, and find their dream man in right there...