Most of us here never did get a diagnosis of BPD, NPD or whatever from a professional. Seems they're hard to get. Still, we know from the patterns what is the likely 'culprit'. So don't be discouraged by the professionals who tiptoe around a diagnosis and studiously ignore seeking a diagnosis. Even though we're not trained professionals (and also too close close to them to offer a diagnosis even if we were qualified) we know what a rose is even if we can't declare a name.
So what we do is follow the lead of the courts and most professionals, we assess and document the behaviors and behavior patterns. We weren't able to 'fix' our problem persons, similarly court doesn't try to fix them either. They deal with them as they are. Follow their lead.
If I choose to make a 24 hour trip to spend Thanksgiving with her extended family (or even go see my own family), would that be viewed unfavorably by a judge should I proceed with an attempt at full custody?
Thanksgiving is a long holiday weekend, often covering up to 4 days. Is she claiming the entire long weekend or just the holiday only?
I don't feel there is any clear downside whatever you decide to do. I don't think the courts or associated evaluators will judge you unfairly or think you're not an involved father if you don't try for every holiday. Since there is no order yet (I think) then they will realize you both ought to be splitting time with the child and increasingly this will be with one parent or the other. Even if you're going for full custody, she may still end up with some parenting time as a non-primary parent. Since you can't be awake and be present 24/7 then obviously she will have time with him when you're not present, at least until the court decides what to do. (Often supervised visitation is not ordered unless there is real risk of child abuse, child neglect or child endangerment.)
By the way, even when there are court orders a parent will usually only get every other holiday, so most of us miss half our holiday events with the kids anyway — by court order.
However, if you want to go the extra mile and seek documentation that you are an involved parent, you can always text or email her what holiday plans you want with your child. If she agrees, good. If not, then you have documentation that you tried and she refused.
Just so you know, there is a hierarchy or priority level when it comes to parenting time. Until you have an order it's almost like possession is 99% of the law. If you have your child and there is no order then you make the decisions. Of course if the police get called they won't care about possession or who says/did what, they'll want to resolve the immediate incident. Which means they'll request you to "be reasonable and let the mother have the child". That happened once or twice with me and the officers ended up walking away and saying, "Fix this in court." Under an order:
- Holidays have the highest priority level. Almost nothing trumps them.
Your county probably has a holiday list detailing which ones each parent gets. She may or may not be willing to switch holidays but generally neither parent can force a switch.
Side point... .when you do address holidays in court, make sure the minor ones neither of you observe are struck out so she can't use them to sabotage your plans. My ex did that. To block my midwinter vacation notice she claimed she wanted to observe Kwanzaa even though she wasn't Jewish. She said that in court testimony and since Kwanzaa is not a Jewish holiday the court knew her claim was "not credible". - Vacations also take priority over regular parenting schedules. You must give advance notice of vacations, at least 30 days in advance or handled by season, your county will have those details too. Remember, vacation notices are notices, not requests. She can't unilaterally say No if a court order is in effect.
- Parenting Schedule is the regular division of parenting time. There will always be times one of you wants to change or trade times. Beware that unless you get your traded time first the risk is higher that she might renege on fulfilling the second half of the trade. That's another good reason to get trades in writing. Having that may not enforce a trade but makes it less likely to fail.