Ive just got back from spending a few days with friends, who live in Italy, and the weather there has been very unsettled, and quite cold as well, a bit like Dyffryn.
The walks that i will recommend, are all fairly easy in terrain, and will take you to a part of North Wales that i can almost guarantee you will never have considered.
Hopefully you will have your own personal transport, as this will make getting to and from your walking locations, that much easier.
Number one walk, is the assent of Cader Idris from Minffordd.
Minffordd is not that far from Dolgellau, and you leave Dolgellau as if you were driving towards Aberystwyth.
Make for Talyllyn, and Minfford and the parking area, is the far end of the lake.
Ascending Cader Idris via Cwm Cae, is one of the finest walks in southern Snowdonia, and is not technically difficult.
The only real problem would be navigation near the rock strewn summit in mist, other than that, its similar in certain respects to an ascent of Snowdon.
My second choice, and due to its doorstep location to my home, is an ascent of the Southern Rhinogs from Tal Y Bont.
Following the old Drovers Road, now used only by local farmers, you can venture anywhere, without really getting lost.
Following the magnificent Great Wall of Wales, all the way to Yr Llether and around to Diffwys, is one of the easiest and most neglected walks in the whole of Southern Snowdonia, very similar in feel to walking the Brecon Beacons, but oh so different, because of their very close proximity to the sea.
Its rare to see any fellow walkers traversing the Rhinogs, simply because they are off the main tourist highway, or a separate area of Snowdonia that few visitors to North Wales have heard about.
If you are able to time your visit with some good settled weather conditions, both Cader Idris and the Southern Rhinogs, near Barmouth, are very close together.
You can of course head towards the main routes further North, such as the Glyders, Carneddau, Snowdon area, but then your chosen walks or routes will be so extensive, that choosing them, will be more challenging.
Cader Idris and the Rhinogs are a separate area in Southern Snowdonia, and therefore are walks in themselves, and not part of a massive area, with so many routes, that choosing one will be a challenge.
Accommodation in Dolgellau, or even Barmouth, this time of year, will be easy, as the tourist industry has gone to sleep until Easter.
I hope my suggestions are of interest to you, and that you will be blessed with fine weather.