I was wondering if makes much difference with running novice horses on certain courses. For example Market Rasen is a easy course where as Exeter is a much tougher course to run.
As in real life certain trainers run there horses on easier courses to begin with to get a feel for racing; does anyone know if this is the same with the game?

I haven't really noticed any difference. If the horse is up to the task, it'll manage just fine.

What you will notice from time to time, is a horses for courses trait. Although, it's a rare occurence, sometimes your jockey will report something like "horse didn't like the left turns", etc.

I've had horse didn't like kick-back when it's raced on all weather....
Horse didn't handle left/right turns....
Did notice one of my horses won 4 races at Newcastle and only had 5 wins to it's name out of 19 starts...
But never seen anything about actually liking a course

I think l only ever had it twice in SO2. Horse liked the track

I think the undulations of a track defeinitely have an effect so some horses may prefer a "flat" track. As for fences, I very much doubt the game takes into account that for example Cheltenham is a more difficult jumping test than Market Rasen.

On an individual basis though it's possible that a ditch takes more jumping than a plain fence. Whether a fence situated on a downhill stretch is given more difficulty, I don't know.

On an even more individual basis it's also possible that fences like Becher's Brook have a higher difficulty.

I guess only the developer could answer some of these.

Add to that:
Would prefer a dirt surface or something like that in the trainer screen.

I have noticed twice the jockey say the horse liked the course after a good run but it then didn`t show up in the jockey feedback speech bubble. Think there`s a bug there but so far unable to reproduce it so waiting for another instance. Also, the horses involved didn`t reproduce the form on the track stated and the jockeys made no further reference unlike in SO3.

The instruction manual in one of the old games said that small horses would like sharp tracks,and large horses would be better suited to galloping courses.Not sure how true this is though.

Courses like Cheltenham do have stiffer fences, it even says in the description of the course during a race. I think even Exeter says 'stiff fences'. Although whether these two courses should be harder for a horse to run around than a nice flat one like Market Rasen I don't know.

I've had a handicapper who has run brilliantly in two graded races at Aintree, both times the jockey reported that the horse likes this course. Although it didn't appear in the speech bubble on the horses' screen, so as someone else said possibly a bug.