Ambivalence about engagement- thoughts?

My boyfriend and I have been dating for a little over 4 years. We have discussed marrying each other next year - since I graduated college and will now be working full time and he will graduate next December. Well he ended up telling me he was going to propose to me this month but now all these questions arose and I can tell he's really struggling with it :/. 
He has a big dream of taking a long road trip and thinks that because of my job I won't want to go with him and will just want to keep working where I am at in a year. I would say he is more of a traveler than me but I still enjoy traveling. 
Problem #2 is that his dad doesn't think I would go on this trip either and sees me as a "city girl" and not able to get "my hands dirty". Overall maybe he doesn't see us being compatible? I was really offended when my BF told me this and hurt when he said he didn't say anything to his dad about it. He's too shy to tell his dad that he's very serious about marrying me. 
He is also nervous about my parents (we both live at home currently and are close with our families). My parents can of course be difficult sometimes and would probably not be too happy about the road trip or wanting to live far away. Also I am very close to my dad and this intimidates him lol. 
For married couples: Before you got engaged what were some serious talks if any did you have ? 
I love him and always tell him I support his dreams and we have talked about compromising when it comes to the trip duration and when we would leave for it. 
But the fact that this trip and each of our parents seem to be causing so much chaos is making me feel anxious :(. I feel like he's questioning everything. He says that every doubt goes away when we see each other but when we're a part it creeps in. I'm just at a lost here.