I've done a bit around the area and I'm actually in Kyleakin just now.
To your first question, there is, from memory a pier near the hotel but I didn't use it and there must have been a reason...can't remember. I think there was visitor moorings if you've got a means of getting ashore.
Have you spoken with the Harbour Master about berthing at Kyleakin? It's used mostly by commercial tour and fishing boats, and they try to push leisure boats over to Kyle of Lochalsh. I talked my way in with a rib but I know he's chasing sailing boats out. (Wafies).
Lewis and Harris is quite adventurous for a 5mtr boat but if you know what your undertaking I'll not lecture you
. Also not much there by way of facilities, even Tarbert in Harris had nowhere you could go alongside with a rib that just really leaves Stornoway.
However not withstanding these issues there are countless cracking places to go. I've just had a couple of brilliant days out with a trip down the Kyles to Mallaig then over to Eigg and yesterday, Rum and Scavaig. (The dolphins are apparently near Canna just now.)
Plockton is only 7mls from Kyleakin and has short term pontoon facilities.. £5 for two hours. Heading north Fladdy is a beautiful natural harbour ideal for a picnic stop, Acarseid Mhor on Rona has a small floating pontoon for going ashore, Good slip at Staffin but can have a bit of a swell running if you're tied alongside.
If caves are your thing there's one on the north side of Trodday, one on the south shore of the approach to Portree and one at the Shaints. I've had the boat into all of them so it's do-able.
If you're visiting Portree (and it's well worth it) make sure there isn't a cruise ship in at the time because they close the pontoon facilities to the public for the duration.......a real bummer. Lochgair (Flowerdale) is also worth a visit if your going that far north.
For scenery, from McLeod's Maidens north passed Niest point is stunning. (Slip at Pooltiel tidal.) and the north west shore of Loch Bracadale has some stunning features. (caves, waterfalls, arches.).
You'll love the place......