Roughly speaking, it is about 0.5psi per ft, so you are going to lose 35-40 psi just going uphill (if it was 20' rise, then 40' rise, then the 18' rise). It would be best to check with the city or take a pressure gage over to one of your neighbors (that hopefully isn't on a hill) to see what the pressure is at the street. If it is say 100 psi, it will be down to around 70 psi by the time it hits your house and should be plenty for what you need. If it starts out at say 60 psi, then you will probably have issues and may need to install a booster pump to get the pressure that you need. However, it sounds like it drops 20', goes up 40', and then up 18'. This is (-20+40+18) = 38' (~18 psi drop). What matters is the net distance that the shower valve is above the meter.
So if we get that starting pressure, we can figure out what is needed to get the right pressure at the house. Once it is at the house, then eveything can be run in standard 3/4" and 1/2" to the fixtures.