Hi there Sam, we have all been there for sure, so we know the situation. There's always a lot to learn even if you have been at it for some time and I thing that's one of the most appealing (and sometimes frustrating) things about Photography. We have the advantage now with Digital that we can take many more frames than we would have done with film and then manipulate then if we need to when we get home.
PP (post production) is another skill completely, and fortunately the internet and endless tutorials are available on line (some good, some not so good). Lightroom and especially Photoshop are intensive tools to learn, especially as they always add more and more options. Fortunately the core tools of these products stay much the same. If you need to do something there's always someone that's posted a tutorial somewhere! Also in some cases there is more than one way to get to the same end. Photoshop now is becoming more Non-destructive (you can undo any edits without permanently altering or destroying pixels) if you use it correctly but watch out as it still can be destructive.
My Son did a similar trip (Route 66) across the States (very Jealous) and when you get back with a LOT of photos it's a bit bewildering isn't it
. Coming back after a trip like that and processing a lot of shots can be time consuming, but as you do it look back and enjoy the memory's too! Be subtle with your processing and it will bring great benefits, I bet you have some great shots
If you want to get into photography and I'll assume you do if your here, learning to use that camera manually will make you king! You will find that on a number of occasions the cameras sensors will lie to you and knowing how to compensate for that is where knowing manual settings is key. But you will have your hands full and a lot to learn, the good thing is you have arrived here and I think this is probably the best Photographic forum there is, there are a lot of brilliant photographers on here and most will help you.
I'm sure you will find you will improve in leaps and bounds and you'll enjoy it along the way (although it can be frustrating sometimes). Anyhow enough of my waffle.
Cheers Steve