I think I've heard this answered before but with Regionals coming up, I need confirmation. If I have winterfell castle in play and the dreadfort, does playing a bolton refugee trigger the Dreadfort's draw response?

Yes.

The reason for this is that the constant effect from Winterfell Castle modifies the card played before the response is triggered in the responses step of having the character come into play.

Thank you. That's what I figured. One argument that I might get is that the dreadfort calls for you to play a card of 3 strength or higher. While the card has 3 str when the response window opens, I never 'played' a bolton card of 3 str or higher. Funny how these things work.

Well, you can always refer people to p. 25 of the FAQ:

" Can I trigger The Dreadfort (Dreadfort Betrayal 105) when I play a Bolton Refugee (Refugees of War 83) with a printed STR of 2, and have Winterfell Castle (Core 25) in play, which gives the Bolton Refugee +1 STR?

Qualifying characteristics of cards are checked at the time a Response effect is triggered. In this example, the Bolton character enters play and has its STR raised to 3 (by the constant effect on Winterfell Castle) when it enters play, which occurs before the Response effect is triggered. When the Response is triggered, the character’s STR is 3, and it has just been played, so you can use The Dreadfort to draw a card."

(The nice thing about that is it also explains why playing Damon Dance-For-Me while Threat from the North is someone's revealed plot will not let you use The Dreadfort.)