I'll touch on the first question. The best way to boost your D1 resume, at any level, is NT success. I don't have a ton of experience transitioning from D2 to D1, but my
Valdosta St resume qualified me for C prestige jobs after just 6 seasons at D2. A HUGE part of that, no doubt, was the FF run we had. At D1 though, it's a whole new ball game. I would HIGHLY recommend waiting until you are qualified for a C- job rather than just jumping into a D- program as soon as you are qualified. D1 is ALL about prestige when it comes to recruiting and there is a vast difference in the recruits you can talk to when you're D-, D, D+, and C-. The reason I recommend C- is assuming you take over a full rebuild, you can almost certainly expect a drop in prestige after your first season and at D+ you can still talk to kids ranked between 50 and 60 at their position. At D prestige, kids ranked between 61-90 (maybe even 100, not sure) are backups. I've never recruited with D- so I don't know what kind of dropoff that entails. But b/c of the prestige multipliers for recruiting at D1, winning battles with a D- is really, really hard, even against simmy.
In regards to your questions specifically, I'm not sure if conference championships or COY play any role in boosting your D1 resume, but the CT championship certainly does since it gets you to the NT.
That said, if your goal at D1 is to get to a big 6 conference, then taking over a program in a predominantly sim-filled conference is the way to go, assuming you can win your CT year after year and make appearances in the NT.