September Travel Advice

Hello! American travelers here, planning on visiting the UK (+ Ireland) for our honeymoon mid September, for about a week and a half, almost two weeks. My better half wishes to visit at least, Ireland, Scotland and England, and if possible, Wales. How feasible would such an endeavor be from a time perspective? Does the Rail pass allow travel between England and Scotland? I know it doesn't for Ireland (naturally). We are currently planning to fly into Dublin first, and then end our trip in London. Looking for any advice when it comes to going place to place, and fun activities to do in each country!