I'm living in a triplex and dont want to use what I'm not renting, specifically. Other than the skylight, the closest window is 20' away, at the top of the stairs coming up to room. It may be used if things expand and the tent gets ditched.A question nobody has asked yet is what's above your ceiling? You can exhaust straight into the crawl space or you can tap into a plumbing vent and exhaust outside.
Ducting straight up to the ceiling would be a lot easier than cutting your door. You're intake is probably not going to be an issue, that door is nowhere near air tight - enough air will came around it to supply your exhaust.
This is inside closet
Bottom, right against rug
Top
What about a narrow, 16"x 2" (ish) vent with cover here?