Crete

Where are you arriving and departing the island?
What are your interests?
Will you be renting a car?
These should give you a good start:
https://www.incrediblecrete.gr/en/
https://www.discovergreece.com/crete

You are only going for 5 days. Everything you might be able to do or see will be in any Crete guidebook.
You can make your choices. Or you can get back on the forum and chase down everyone’s replies. See if they work for you. Maybe not. Some might say Knossos was great. I disagree. So there you have it. Opposing views. Do you want to wade through that or do you want to go without preconceived notions and retain your sense of adventure.

We spent two weeks in beautiful Chania and did a day trip to Heraklion to visit the antiquities at Knossos. With only five days, stay in Chania. We rented a car and explored western Crete.

The wine tasting and light lunch at Dourakis Winery was a fabulous experience!

Depends on your budget and what your criteria is for hotels. In Chania, we stayed at Porto Veneziano Hotel.
It was great!

ONe important thing is going in early Spring ... when you choose a hotel, be sure it is one that has an independent heating system -- not just one that works off the A/C ... the latter are insufficient when the weather turns wet & windy, with night-time temps in 50s F.

The guidebook series both have good guides to Crete: The Rough Guide to Crete, and The Lonely Planet guide to Crete. You could also check guidebooks to Grece: the Rough Guide, Lonely Planet, Fodors, possibly others. For what Rick Steves guides don't cover, those are my 3 favorite guidebook series, in that order. For hotels, i have had good luck finding hotels on booking.com, but use the guidebooks and blogs and Google maps to confirm that the hotel you think you want is in a good enough location before you reserve a room.

In Crete in October 2018 i stayed in Heraklion and Chania; Heraklion looked like it had a retaining wall instead of a beach, and some people don't rate the place highly, but my experience was good anyway. In Heraklion, stayed at a hotel called El Greco. Its about 2 to 3 stars and did the job quite well.