Too many options!

You are right, this is complicated. There is one axiom related to travel that is constant: you can't see everything on one trip. I don't quite follow all the moving around you are thinking about, but in my opinion it would be a mistake to miss Glasgow. We've been there for about thirty days on various trips and will go again. Maybe you could substitute a distillery or a Scottish brewery for Guiness.

We beat the ferry business to death a couple of days ago: http://www.ricksteves.com/graffiti/helpline/index.cfm/rurl/topic/97615/glasgow-to-bushmills-irelandferry-for-cars--cost-and-time.html One brewery looks about like any other one. The Guiness place is more of an advertisment/museum/tourist trap. How much stuff will you need to tote on Ryan? You'd better read their stuff very carefully - - the apparent bargain can disappear if you're not careful. The Edinburgh aiport is really easy. Dublin about average. Neither are real close to the center of the cities, so there's time and money involved there.

My husband is a longtime Guinness drinker so being close by and stopping for a visit is appealing to us. We know it's touristy but that's what we are! Besides, saving $600 ion flights is even more appealing. If we do take the ferry on foot to Dublin, how expensive would it be to take a taxi into town?

Karen, I most definitely wouldn't take a "day trip" to just see the Guinness Brewery at St. James Gate. While it's somewhat interesting to see the process, it's not really that interesting. The "free" pint in the Gravity Bar at the end is a nice treat though. The Souvenir shop is on the main floor, just after you enter, so you'll be going past that both at the beginning and end of the tour. For that tour, I'd suggest that you have some flexibility with your time as there can be HUGE queues at certain times of the day. In terms of historical sites in Dubin, the Kilmainham Gaol is much more interesting and significant (IMO). In addition to its historical significance, it's been used in a couple of movies including the original Italian Job (Michal Caine) and In The Name of the Father (Daniel Day Lewis). For travel from Scotland to Ireland, I'd much rather fly from Edinburgh to Belfast via EasyJet and then take the train to Dublin (anything to avoid RyanAir!). I believe the new Titanic Museum is now open in Belfast, so perhaps you could fit in a short visit there. Taking the rental car from Scotland is not a very "efficient" travel method and taking it on the Ferry will likely cost more than a budget flight. Good luck with your planning!

Beats me on a taxi, it's four or five miles, maybe twenty bucks? The centy center bus fare costs less than a euro. Figure three times that since you're wide on both ends? There's bound to be a line change around O'Connell Street.

It looks like there is an express bus from the port to Connolly station in Dublin for €3. While not a taxi, it might be a good option for you to get into the city center.

Karen, that's going to be the most expensive glass of Guinness your husband will ever drink. And he won't be in the brewery itself, but in a warehouse converted into a mixed-media display. Admission with an on-line discount is 14.85€ https://www.guinness-storehouse.com/en/Ticketion.aspx and that includes a single pint of beer. As to flying RyanAir from Edinburgh, I see June seats at just over $100 Canadian with one checked bag but no seat priority. Aer Lingus, my preference, is slightly cheaper. Getting to and from an extra airport adds to the costs and suddenly your $300 saving is dwindling away.
I'd skip the hassles to enjoy the atmosphere in Edinburgh where the Guinness tastes exactly the same. P.S.: Dublin is worth a trip all on its own, but so is Glasgow.

Karen, If the Guinness Brewery is the main draw for Dublin, then I have no hesitation in saying that you will be disappointed! First of all you are not actually in the brewery, you are in the storehouse and most of what you see will be a media presentation... the view from the gravity bar is great and the Guinness is good, but not worth the trip for that alone. Jim

The trip to Dublin is not just to go to the Guinness Storehouse. That's a bit of a bonus. It's the $600 we will save on our flights by flying home from Dublin instead of Glasgow. I think the plan is to drop off the rental car in Holyhead and take the ferry across and spend our last day and a half in Dublin before flying back to Toronto.

Hi Karen, Have you made a 2 week calendar and written day by day specifically what you have planned?For the car portion, try going to Michelin.com and search your routes to see how much time you can expect it to take, then add about 1/3 of that to get a good idea of time. It's quite a distance from Bath to Scotland. As a rule, you can count on spending about 1/2 a day every time you change location. By car, you can count back some of that in sightseeing opportunities if you plan your route right. It just seems to me that you have too much planned for 2 weeks. For me, $600 saving on a flight would be a high price to pay for missing out on 2 to 3 extra days in Scotland, especially since you already have a car. And you are going to spend a good part of that saving getting to Ireland. We did the Guinness Storehouse. On a 10 point scale, it was a 3. You don't see the brewery, but you will see MANY tour busses. Just some thoughts. You are going to have a good time regardless of what you do. Best regards,
Thomas