What power tool to speed production

I am bulding an addition to a frame I built last year. Like the original, I am using all hand tools except a chain saw to cut timber to length. If all goes well with this addition, I will build a larger frame after I retire next year.
What power tool woud most speed up the process? I use a boring tool for my mortises and I think a power mortiser would probably be the biggest time saver.
I have tried using a 7.25 " power saw for cutting shoulders but like my handsaw because I am just as or more accurate and the additional time using a handsaw is insignificant. Is a mortiser the first power tool to consider?
Thanks,
Bob

The chain mortiser and circular saw seem pretty standard for working timbers with power tools. You should be able to cut right to the line with your circular saw, and the chain mortiser when possible.
IMO, it's the brain that is your biggest time saver or waster.

A suite of same brand cordless tools (18v size) seems to work well. I use Bosch drill/driver, planer and recip saw. The batteries recharge in less than two hours. One battery charge did all the holes in a 15x24' cypress frame for a bus stop.
These tools are heavy and rugged, not your hobbiest lightweights.
good luck
deralte

I think a chain mortiser will save you the most time. Get an extra chain (so you will always have at least one chain while the other is being sharpened), unless you plan on sharpening your own.