Going by various sources we know a few things, but not the full details:
-Will run between Edinburgh/Glasgow to Aberdeen/Inverness
-Hourly service between Inverness-Perth
(alternating between Edinburgh/Glasgow)
-Hourly service from Aberdeen-Inverness
-Express service (suggests limited stops)
Here's when things such as calls get taken into account. With the announcement of 13 turbostars being retained by Scotrail, many new services will affect the HST timetable (presumably)
Aberdeen Crossrail - Local hourly stopping service from Montrose to Inverurie/Insch/Huntly. This suggests that HSTs can afford to speed up by missing the following calls: Montrose, Laurencekirk, Stonehaven, Portlethen, Dyce, Insch, Huntly on routes from Glasgow to Aberdeen and Aberdeen to Inverness.
Dundee/Arbroath Local - Hourly(?) stopping service between Glasgow and Dundee/Arbroath. This suggests that the HST can also afford to miss the following calls: Larbert, Dunblane, Gleneagles, Invergowrie, Broughty Ferry, Monifieth on routes from Glasgow Queen Street to Aberdeen, Edinburgh to Aberdeen (from Dundee) and Glasgow Queen Street to Inverness (as far as Perth).
Perth to Edinburgh Local - Hourly service between Perth and Edinburgh as currently in place between certain times. This also suggests that HSTs can possibly afford to skip the following calls: Ladybank, Markinch, Kirkcaldy (?), Inverkeithing (?), Edinburgh Gateway (?), which could see services between Inverness and Edinburgh being diverted via Stirling, running non stop from Perth to maximise journey times. It also adds the possibility of more Dundee to Edinburgh local services (which I think are happening?). Although diversions only usually happen should the service run a minimum of 10 minutes late so we can expect it to call at Kirkcaldy and Edinburgh Gateway at the very least.
So, going by what we know already, we can get an idea of the most likely service patterns for HSTs, although we can never be sure.
Glasgow to Aberdeen
Glasgow-Stirling-Perth-Dundee-Arbroath-Aberdeen
With infrequent (2 hourly?) calls at Dunblane, Gleneagles, Montrose, Laurencekirk, Stonehaven. So that leaves us with the possible conclusion that Glasgow to Aberdeen services could alternate between Fast and Semi Fast journeys, speeding up 50% of diagrams currently in place today.
Aberdeen to Inverness
Aberdeen-Inverurie-Keith-Elgin-Forres-Nairn-Inverness
Also with semi-fast service calls at Dyce, Insch and Huntly. But judging by the service patterns currently in place, the calls for that particular journey probably wouldn't change due to the nature of the route inhibiting frequent services, thus calling all stops.
Edinburgh to Aberdeen
Edinburgh-Haymarket-Edinburgh Gateway-Leuchars-Dundee-Arbroath-Aberdeen. Taking into consideration the current service pattern and the future connectivity to Edinburgh Airport, as well as future service between smaller stations. This service could also see alternating timetables between Fast and Semi Fast with the stations listed coming under the former. But we can expect a call at either Montrose or Stonehaven to connect with local services.
Edinburgh to Inverness
Edinburgh-Haymarket-Edinburgh Gateway-Kirkcaldy-Perth-Pitlochry-Kingussie-Aviemore-Inverness. This service could be in a similar situation to the Aberdeen to Inverness service in which smaller remote calls will be called at to boost connectivity. Judging by current services it would be most likely that this service will only get improved journey times pending on the acceleration which is the most probable case for most HST journeys.
Obviously we can't know for sure what the service patterns are going to be, but gathering a few facts we know that services will probably cut out a few stations, which will be served by new local services, which will see Intercity services call at smaller stations on a less frequent basis. I.e from hourly to 2 hourly etc. Mind you, this is just my personal opinion