In June 2022 I am planning a trip from the USA to Anglesey across North Wales, then to Shrewsbury and up to Inverness and the Orkneys, allowing about one week each for Wales and Scotland. It needs to be in that order because my third week is studying at St. Andrew's Univ. I'll be travelling alone with luggage on public transit. Driving would be easier if the UK didn't use the opposite side of the road -- I'm afraid of having an accident.
I've considered flying into Dublin and taking the hydrofoil. With Manchester, Cardiff, and even worse London, there'd be doubling back. OTOH I don't know about the difficulty of transiting from the Republic to Wales. Last time I did so was over 20 years ago.
Of course COVID could knock everything topsy-turvy, as I don't have the time or resources for a long quarantine. I would like your advice assuming that travel will be no worse than in 2019.