So guys... I DID IT!
We travelled all the way down to visit the relative

it took about 6 hours down (some bad roads and weather) and about 5 hours back.
I didn't know I was going to do it and in fact had told my husband that morning that I was planning only on achieving the stateside breakfast and that was more than enough for me. He said 'let's do breakfast and just see how you feel'.
Well I felt really crappy about it - very anxious and feeling sick from the anxiety and overwhelmed by the task ahead of me.
It suddenly occurred to me to take an Ativan right then. As I said I usually just take one when I have a panic attack I can't seem to get under control or am not in a space I can relax in. But I remembered a couple summers ago I wanted to meet a friend downtown and my option to get there was the city bus - that morning as well I had wanted to do it without a med but then thought, 'do I want to spend the morning fighting panic just to prove I can do it without Ativan help, or do I want to start off in a calmer state of mind and ENJOY my time with my friend?' They are BOTH forms of success!
I took the Ativan that morning and it made all the difference. I didn't even feel a need to take another as the day went on because I'd started off well and continued well (dealing with lesser degrees of anxiety off and on).
So I applied that to the cross border trip. I think it was also a good idea because not only would it help me calm down and enjoy things but it would keep me from associating the very high levels of stress and anxiety/panic with crossing the border. I might have unwittingly allowed myself to reinforce the idea that crossing the border brings panic by not having ensured a calmer state of mind via the Ativan, and that could make subsequent attempts just as difficult.
Anyways, I started calming down. I was still anxious but doing much better. The border crossing went well. Then we went to get money at a gas station before going to the restaurant and I suddenly just thought 'lets keep going'. So I said that. And we just kept driving onward.
About an hour into it I got really emotional - just happy - I kind of couldn't believe I was doing it. Traveling outside of my 'areas' is one of my biggest fears and limitations, and it was almost like I was looking down on myself there in the car and I realized I was doing it! This was WAY out of my area!
I'm not saying any of that to brag in a bad way, but to celebrate and to try and explain what it felt like.
Various points of the trip brought various degrees of anxiety - it wasn't all clear sailing but I managed it each time it came up (and without any more meds).
Travel is not suddenly easy now but I am so encouraged by that trip and by somehow managing to achieve something I truly thought was far beyond my capabilities. (Not to say we should feel pressured to make those leaps - they're not always a great idea! I know that first hand!)
One lesson I am taking away from this is that it seems to be a good idea for me to start off in a calmer place - to not force myself to wait until I'm in total panic to take the Ativan. I will remain responsible with that medication but I could possibly achieve way more if I allowed myself to make use of it a little more often and earlier on.
ForeverYoung - yes

I remembered that idea on the trip - feeling the fear and doing it anyways. For me this time it also included feeling the emotional tiredness and doing it anyways.
I'd brought a book of meditations with me on the trip and laid in bed the night previous to the drive into America reading a few and read one which contained the words
'Light the lamp. Though the oil has run out, light the lamp anyway, and we'll do what we can.'
(The full meditation gives more context to this but I think this is sufficient for here).
There are times to step back and rest but I felt this was a time to move forward despite my body and mind telling me in many ways that it wasn't going to happen.
It still feels a little unreal that I did it. I am far from 'cured' but I really felt the world open up in front of me as I did that. I felt ME open those possibilities for myself!