as we don't have any sightings except the one, there isn't a whole lot I can add, but here's my two cents...
I definitely think they could survive for awhile on $4500. I also think it's highly likely he squirreled away at least an additional $500 or so. If he was hiding this whole thing from his wife and family, it's easy enough to believe that he might have said the car needed an oil change or some minor repair work, so he was withdrawing $50 here or $100 there. Maybe he did grocery shopping and kept $25 or $50 every so often. I think even on a limited income, he would be able to save some... I also think he was planning an "escape" for some time. Even if it was more of a dream than a reality, and only became more of a reality as his "real life" started crashing around him.
On $5000, they could get pretty far and live for a good length of time, unfortunately. Ramen, easy mac, sandwiches, even mcdonald's, gas or a super cheap motel or campsite each day, and they could probably live on $30 a day, less if sleeping in the car. In smaller towns I've seen hotel rooms for around $20 a night. It wouldn't be the lap of luxury by any means, but a shower and a bed, maybe a tv with a few channels. Those kinds of places aren't super concerned with security or credentials or anything, and always take cash, so as long as they didn't cause trouble (excessive noise, etc), then I don't think anyone would think twice about renting a room to Tad, especially if she stayed in the car while he went in to pay.
I think the major key to getting her home, is coverage in the news, on the radio, etc. that she is welcome home, no matter what she has done or anything. That when she comes home, she will be welcomed with open arms, no judgement.
I don't think it's helpful for anyone to say that she is 100% there against her will or anything like that. True or not. She likely feels that she has played a big role in this, so the "no judgement" factor, would be a better stance. I guess what i mean is that she isn't 5 years old and wasn't abducted from her bed in the middle of the night. Obviously it is an abduction, but the feelings are more complicated than that.
For now, it's possible (and likely) that she is complicit in keeping them undiscovered. I honestly believe that the best way to get her home is for her to know that no one is going to be spinning stories on this, especially those closest to her. That no one wants to gain anything by her return, except her safety, and that she could have a bright future after all of this.