This is my first time to Japan and I am travelling 2 people (me and my mom), travelling from March 31 – April 6. I have some questions that I still confused about. Really appreciate your help/thoughts/advice:

1. My flight will arrive in HND around 5 a.m., after immigration I think we will be out by 5:30 am. Planning to go straight to Hakone. Will spend 2 days 1 nights in Hakone, I heard there is Hakone Day Pass, is it worth it? Our hotel is in Hakone-Yumoto station for March 31.
How to get from HND airport to Hakone Yumoto station by train? which line (JR, Odakyu, etc) and how much does it cost? can we pre-purchase it in the states?

2. If we buy Suica card at the station, can we use credit-card like Sapphire Preferred or Barclay Arrival to load it? And can we use Suica card in Hokkaido too, especially in Sapporo and Hakodate?

Since it’s less than 7 days, we are hesitating to buy JR Pass since it cost around $250 at current currency conversion. And we heard we cannot use JR Pass in Hakone since it’s mostly run by Odakyu. We only in Tokyo for a night , then fly to Sapporo by plane. From Sapporo we will go to Hakodate (I check it’s by JR Hokuto express line). I heard most stores/restaurant in Japan don’t accept credit cards. So if we can buy Suica and load with miles/points earning credit cards, that would be better. Otherwise, we can to buy JR Pass in USA first by using credit cards so can use unlimited ride in Hokkaido only, but we only stay in Hokkaido for 4 days so maybe not really maximize the value of JR Pass, only use it for maybe Shinkansen from Tokyo to Odawara before using Odakyu line for Hakone trip, and then use it in Hokkaido, and then for HND - NRT transfer including Keisei Skyliner, so not sure about going this way…please advise.

3. Can we pay by credit cards if we buy something at konbini (convenience stores like 7-11, Lawson) and eat at ramen or sushi restaurant?