You want to plot out Air BnB to find some cheap places tho outside the major cities motels are cheap too.
Depends on how many KM you put on as well.
Mine is likely typical getting 20km per litre on a 35,000 km base. That's $30 or so on fuel for 500 km ( figure its cheaper in the US)
Food is cheap in the US. You can do $20 but carry your own drinks.
Motels are the biggest variable. $50 is possible in the more remote areas but I'd say $80-120 if you are going to say Washington.
But the remote highways in between can be very cheap and competitive but you may not find places depending on when you are travelling.
That distance you almost certainly will do in a tire - CAA plus a very good idea. Figure $200 for a tire mounted if you aren't proactive on it. You should count on an oil change or two.
You'll needed extended healthcare as well....CAA can provide that. I'd get a year long deal that covers up to 30 days continuous - you can then extend that.
Some credit cards give you a bit as well but nothing like long term deal.
Honda might be easier/cheaper to find parts if things go wrong.
This is useful for interesting rides.
http://www.motorcycleroads.us
as are a number of cell phone maps that do not need a data connection.
I use ForEver Map - and just got TomTom but it's $$ but has voice guidance without needed data. Roaming is expensive.
There is a cool app called Glympse that lets people keep track of where you are.
All MacDs have wifi.
I think it really depends on how much slab you are doing versus mcycle roads.
Slab can be cheap.....good mcycle regions require some work and planning.
Someone else mentioned a hostel network as well which can make major cities cheaper.
Sounds like fun.

but I'd skip the straight South leg, do East West instead - the East can always be done later - there is just too much good on the West Coast
If anything a long triangle going west to the Seattle area, south along the coast to San Fran and then La and then angle back across
There are others here who can advise that better