I have done a bunch of munros in Scotland - I also spent four months doing a geology mapping project in NW Scotland on extremely challenging terrain. I was pretty fit at the time but I ran up Ben Hope in about 90 mins or so. If you have a good base level of fitness, these walks will tire you but you will manage them - I have seen 70 year olds at the top of munros before! There are well documented routes on all the munros (& corebetts) and they are kept maintained just with the sheer amount of foot traffic.
Strictly speaking there shouldent be any actual climbing per say just walking uphill so big strains on those thighs, knees & calfs. Wear good, comfortable waterproof hiking boots. Prepare for many different types of weather conditions - we had to deal with rolling fog that reduced visibility to a few meters but as I mentioned above the tracks were easy to follow even in theses conditions. Wear light comfortable clothing also. Depending on if you are going in Winter or Summer - dress/prepare accordingly. Breathable clothing is awesome if you can get some. Best to start out a layer down - 'chilly' as you will warm up quickly - the key is to stay warm & dry. Invest in decent hiking bags - I reccomend Berghaus - you want a bag with excellent back support characteristics & obviously pack light!
Also, bring GPS, compass & map of course. I know its sounds silly but have your route pre-planned and stick to it. We almost got ourselves in a tight situation when we went off route on a munro before & fog came in.
Bring high calorie foods of course - your typical fruit bars, packed lunch (I always bring wine gums & jaffa cakes too!) & PLENTY of water. You would be surprised how much liquid you lose even on a cold day.
Typically, your route will depend on your pace and choice of route and the difficulty of the munro/hill/mountain etc. But expect the round trip for each to be at a minimum of 3-4 hours.
My lecturer and I on top of Ben Hope. That stone to the left is called the "cairn" stone and marks the top of the Munro. Not sure what marks the tops of the other hills you will be going up but Ben Nevis will certainly have one. You can see from the pictiure the fog we are in - that fog was cold! I would say it knocked about 5-10 degrees off the temperature up there. That day started off bright, warm & clear - so you can see how quick things change!