Location of Water Service Cutoff

My house was built back in 1940 and had all galvanized pipe which were badly corroded on the inside. I've removed all the supply pipes the entire DWV system and plan on re-plumbing the house with PVC dwv and PEX. I'd also like to replace my galvanized water service pipe from the street but I've got a couple of questions and concerns...

- highest fixture is 3rd floor shower head (30' above the water meter)
- pressure is between 55 - 65 psi at outside faucet
- meter size is 3/4"
- meter is 50' from house
- located in NC
- clay type soil
- maybe some landscape irrigation in the distant future

1. What material and diameter pipe should I use for the new water service? HDPE ? Is 1" too small?

2. What are the code requirements regarding the location of the main cutoff inside the house? The place where the water line will enter the basement can't be reached without a ladder so I was wanting to run the water line continuous another 30' or so inside the basement to a location under the bathrooms where the cutoff valve could be conveniently located. Is there any code requirement that calls for a cutoff within X number of feet of the entrance point?

3. Once inside, at what point should I transition to pex? Is right past the cutoff valve appropriate?

Thanks

I don't think I would what 30' of pipe in my basement that I couldn't turn off no matter what the code was. Put the valve where it first enters the house and install a second valve at the convent location.
A 1" main should be fine.
Convert to PEX after the valve.

John