No worries about the ferry Luke, i have a laptop with 2 batteries that i intend to take fully charged and an iPod as well with some movies preloaded on it.
The shorter driving will be much better on fuel as having done stranrear so many times i've lost count either as a passenger or driver as the years have gone by the roads may be better but the average speed has come down it does take that much longer.
last time i did the dublin route it was gale force 5 winds in the sea and we spent 18hours on the ferry at the otherside of the harbour waiting to go out. when we did the captain certainly had full power selected as everything in the kitchens and so on was tied down and people told to stay in cabins or on non movable seats.... I've got some really good earplugs as well so i'll find a nice quiet area, keep a credit card and about £10 on me and likely get some sleep on the first ferry ( 0300hrs sail time!) and likely watch the movies on the return. I dont get bored easily as i can always do some training material as well.
£179 from liverpool to dublin
£240 from Holyhead/stranrear
add 2hours of extra fuel, even at cheap rates i get now
each way is still another £60-80 depending on how fast i go!
i remember taking the HSS before the speed limits were imposed on it
that thing really flew down the loch, gosh i even remember when the seacats first came in and ferrys even left fleetwood(not the mac!) on a regular basis.
The rover, well how rust free is it?? Honda engine IIRC so should be OK though bodywork, was, well rizla thin!
PS if you want the Lag bringing over i still havent booked yet(waiting for holiday authorisation!) so if you have something for me to drive back in and around in for the day before let me know
and the cheapest i can get is liverpool-dublin for about £180 and its an 8hour ferry each way... If i go the northern routes the price is nearly £260 return never mind the fuel upto stranrear/cairnryan/troon which is a good 5hours and 3times the milage without any traffic or stops and i know from warrington 3.5hrs is possible.... but thats mainly M6/M74/A74 and i know the A74 has more radar guns than a top secret MOD base these days 
