4 days to hike in Scotland

Certainly Inverness, it's closer to Scottish Highlands and scenery. I would contact Visitor Center in Inverness and ask for suggestions.

Take a look at the HF Holidays in Scotland.

https://www.hfholidays.co.uk/destinations/uk-and-ireland/scotland/

They have their own country houses where you can stay with meals included. You can book a 3-4 night stay with either guided or unguided hiking. Each place comes with instructions on how to get there, and the price for guided hiking includes transport to or from the hike.

If you could get three more days, the West Highland Way is an epic walk.
http://www.west-highland-way.co.uk/home.asp

Start from Glasgow, finish in Ft William. Train back to Glasgow:
http://www.west-highland-way.co.uk/home.asp

There are innumerable walking routes all over Scotland but rather than think of routes first, it would be better if you decided on an area to stay. For example, stay on Skye and discover the island on foot. Or you could do the same on Mull or Loch Lomond or Dumfries and Galloway.

Look at his site to see what appeals http://www.walkhighlands.co.uk/

By the way, in Scotland, the term hiking means more like backpacking with full kit and camping. Walking routes are what you're after.

I am glad that someone referenced walk highlands. It is a great resource. Personally, I would hesitate to say that the more dramatic scenery is nearer to Glasgow. There is dramatic scenery all over Scotland. I liked being based near Inverness as we could go east, west, south or north based on the weather, which can vary by geography. Due to the mountains, lochs and sea, you can get black cloud in one area, sun with mixed showers in another.

My favorite walks include:

• Glen Affric--you can circle the Loch in this most beautiful of glens in a day walk.
  
• Ullapool Hills--this can be shorter walk where you just hike up to the top of the hill, admire the stunning view of Loch Broome and the Summer Isles and then laze a bit in the heather. Or you roam some of the many other trails. Or you go explore Ullapool.
• Torridon--this is an area in the west easily accessed from Inverness that has very striking scenery. You can walk around the lochs or up the hills.
• The Cairngorms--Also easily accessed from Inverness. There are numerous walks in Rothiemurchus Estate and in the park with a wide range of walks. The heather in August is fantastic.
  
• Culbin Sands--if you have a hankering for a beach walk and can't get to the Outer Hebrides, this forest is just east of Inverness and is terrific. You can see many water birds, seals, dolphins, and beautiful views of the Moray Firth.
• Dunkeld Walks--this area is in Perthshire. I have mostly done the easy stuff, but there are many walks. There is the added bonus of The Taybank, an outstanding pub that often has traditional music.
  
• Sligachan--this is on Skye. Skye has numerous challenging walks and I would stay on the island to do them. The walk we did was up the valley and to the point where we could look down and see Loch Coruisk.
  
• The Trossachs--okay, I have not walked here much at all, but I know that there are some great walks. I want to explore the area at the end of Glen Balqhiddar.
  

BTW do plan on hiking boots and a serious rain jacket. I recommend rain pants as well. I have found that a midgie hat can be very important at times. I like hiking sticks. The trails are rocky and boggy.

Pam

We spent a month in Scotland in the fall, and hiked nearly every day (we lucked out with gorgeous weather).

I agree with Pamela - Glen Affric was wonderful, and there is lots of amazing hiking in the Trossachs and in Torridon. If I had to pick only one place to recommend, I might go with Skye. We spent 5 days there, and the landscape is quite remarkable. Skye has a Michelin starred restaurant, Three Chimneys, in a gorgeous/remote setting - make sure to book ahead, but it is worth the effort.

Have a wonderful trip!