Answer: I think your plan and your timing are both right on! Seeding your lawn will be much less expensive than sodding. Once you've finished tilling up the old lawn, rake out the debris. If you have access to some compost, spread 3-4" over the top of the area and til it in. Then rake to level and broadcast your seed.
I suspect that Bermuda is planted because it is a warm season grass and remains green as long as the weather stays warm. It is often overseeded with perennial rye in October so that when the Bermuda goes dormant, the rye greens up. When the rye dies down (during hot weather), the Bermuda greens up.
Kentucky bluegrass is the second most widely grown cool-season species in your area because it has a dark green color, a medium to fine texture, and, due to its aggressive rhizome system, can recover from stresses. It prefers fertile, well-limed soils and full sun to moderate shade. Kentucky bluegrass is often mixed with other cool-season grasses like tall fescue to enhance the ability of the turfgrass stand to recover from stresses.
There are other varieties that have trialed well in your region so you might want to visit the following website to see what the university has to say about the turfgrasses available to you. (It's from North Carolina but I think your zip code puts you in close enough proximity.)
Good luck with your new landscape!
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