Tourist in MSN

I had no idea what the goal was here, so did a quick google search. Is this what you are doing? (Pasted):
AIDS/LifeCycle is a 7 day, 545-mile bike ride from San Francisco to Los Angeles, co-produced by and benefiting San Francisco AIDS Foundation and the Los Angeles LGBT Center.

If so, that sounds like up to maybe 100 miles a day for a week. Probably on roads with a maximum uphill slope of 8 percent grade. But you might want to contact the ride coordinator and ask what the steepest hills are. You do not want to have gearing for 8 percent if you have 12 percent grade hills.

Before you start thinking of an 11 speed system, find out if your rear hub can take an 11 speed cassette. You might want to stick with a 10 speed system if your rear wheel is good but can't take an 11.

Do you need to change your crankset or not? If your shifters and derailleurs are shot, your crankset might be fine or it might only need new chainrings. I have a compact double 50/34 on my road bike, those are very common. But some are moving to smaller rings like 46/30. Best to know which crankset you will want before you decide which cassette you will have. And if your crankset is fine, no reason to change that. That said, if your crankset has a 39T smallest chainring, then maybe you want a new one for lower gearing?

And if you do not have any knee problems with your current crankset, is there a reason that you might want to switch to different crank arm lengths? You did not say what your crank arm lengths are.

I am about 6 foot, inseam similar to yours, I use 175 mm on most of my bikes, one bike has 170mm.

I know I did not answer a single one of your questions, but if you want good advice, that advice has to be tailored to your situation.