Have no fear - St. Fagan’s is one of many things in the Cardiff area that are on the map!
And as for driving “into” London - not really. We’re going to skirt around to where our AirBnB is, park the car and use public transit until we leave! (We learned that lesson more than 20 years ago!)
Did I warn you about asking for an automatic if you don’t want gears? Friends of mine got caught with that one, so only one of the four could drive their hire car! Glad you are park’n’riding! Reading was as close to London as I fancied driving!
Henddraig, you are so caring! Actually, we’ve been driving in Britain whenever we come for more than 20 years, and we request a stick shift. It makes it easier (for me, anyway) to make the switch to the other side of the road when the gear shift is on my left instead of my right. We both drove a stick here anyway until recently; I still do, but not for much longer - I’m getting a new car and it doesn’t come with a stick! I will really miss that!
I know there a number of fantastic routes you can take from South Wales up to Dolgellau - as people have suggested, through Pembrokeshire and Ceredigion, or through Llandeilo and Carreg Cennin castle - but I think one of the best routes to take, with a large variety of things to see is up the A470.
It is a major route, but just off it you can visit Aberfan ( it really brings home the extent of the disaster), Merthyr Tudfil ( ironmasters and Joseph Parry). Then onto Brecon and Builth Wells (Llanfair yn Muallt) over the Beacons. At Rhayader (Rhaedr Gwy) is the kite feeding centre and then, instead of the A470, one of my favourite roads in Wales, the Aberystwyth Mountain Road, from R hayader through Cwmystwyth to Devil’s Bridge (Pontarfynnach), either directly from the middle of town or via Cwm Elan, with its lakes and dams. At Devil’s Bridge is the hotel and waterfall which featured (as a children’s home, I think) in the first or second episode of the first series of Y Gwyll /Hinterland, Tom Matthias clambering down the waterfall for evidence. From there it’s just a short drive to Aberystwyth.
Unfortunately not a great deal of evidence of Welsh being spoken on this route.
I suspect the words you were looking for are 'fussing old silly!" Not sure how to put the concept in Cymraeg!! Think Dili Minllyn in Guto Gwningen (ie Jemima Puddleduck in Peter Rabbit!). Except I can’t cook cakes!
I gather that modern cars are coming with 6 gears nowadays. I like a manual gear shift myself, but I’m not sure I could cope with 6 gears. It took me long enough to adapt from the (then) usual 4 to the (now usual) 5. (Is there really a need for more gears, or is this just the car makers’ version of Spinal Tap’s amplifiers going up to 11? - sorry to drift way off topic… 
).
And even more off topic, I hired a modern car recently and was amazed enough by all the touch screen technology to vow never to own something with so many distractions. I’ll happily keep my radio on Radio Cymru (or R4) for the whole of a journey without needing to fiddle with anything or feel I’m missing out on anything digital!
But on the plus side a proper sat nav does avoid many a country lane detour 
I wouldn’t trust a sat nav, frankly. I’ve heard too many stories of people being directed into open fields, or down dead-end lanes, or large trucks being directed down lanes too small for them (etc, etc,) to ever trust them! They rarely even find my house properly! I have maps and am good at reading them; that will do for me.
I do hope your sat nav does not send you up incredibly steep hills with rough gravel surface and ruts! Or through farmyards or down single track lanes just as the cows are coming up for milking! I could name other interesting sat nav efforts with a bit of thought. Especially applicable to lorries and minibuses, of course!
Oh @Sionned I see we are coming from the same direction here! I could show you a hill on Gower which scared the wits out of any city driver In a car,never mind a lorry!
I tend to agree. Having said that, sat-nav seems to be about the only way anyone finds us - since the post-code is just for us and the house next door, whereas descriptions of where to turn seem to send everybody, always, to y Fron…
If I had known that, I would have asked you for it – I assumed that rural postcodes would cover square miles simply because the number of houses per square mile is so much lower!
But using 3 word addresses was more fun anyway, at least for me At any rate, I knew pretty much exactly how to get there.
@aran, I have always believed in asking directions and fitting those to OS maps! If I was still driving and needed to visit you, I would ask, “please give simple hints like (name of pub) , turn left, at next junction, turn right etc.” I used to navigate for car rallies (not the professional kind) and only got a little bit lost on rare occasions!
[quote=“aran, post:31, topic:7613”]
Having said that, sat-nav seems to be about the only way anyone finds us - since the post-code is just for us and the house next door, whereas descriptions of where to turn seem to send everybody, always, to y Fron. [/quote]
Well, y Fron is not all that far away . . . But now I’m curious - how close did I get your marker?
Impressively close - we’re about two minutes out of Carmel…
While you’re in Dolgellau, I recommend a visit to The Cross Foxes. It’s our stopping point when we drive from Gloucester to Ynys Môn. The food is lovely and a great atmosphere.
I would be happy to meet up for a drink while you are in London
Oh if you are going to London @Sionned , I suppose one should consider looking in at the London Welsh Centre (but maybe that was already on your wish-list).