Some of the answer depends on your particular locations and the practices/conditions there. So a local Realtor really is your best source. However, in general:
Answering your second question first, no, it's usually not a plus to have the unit furnished. Most renters have their own furniture. Generally, the only time it makes sense to offer a place furnished is for a short-term rental, particularly a corporate rental. But if you're thinking of a lease of a year or so, it's generally to your advantage to lease the property without furniture.
You say: How to market it. Do you mean: Once you buy it, how do you rent it out? If so, there are two basic routes to go. One is do-it-yourself, advertising on Craigslist, your local newspapers, fliers in supermarkets, that sort of thing. I did that for years with a rental I have. Many, many people choose that route.
The other option is to list it with a Realtor and have it listed on the MLS. My sense is that fewer properties are rented this way, and--again--you'll find a lot of variation by location. Still, I decided to do that with a property I have and it's worked out well. The quality of renter (far less likely to be flakey) is much better. There is a cost--around where I live it's the equivalent of one month's rent (but commissions are fully negotiable). That's the way I handle it now. And even though I'm a Realtor, I use one who specializes in rentals.
What you really have to make sure of is that rentals in your area will cover the costs of ownership. Again, that'll vary greatly based on location. From what I understand, though, you may well be in an area where financially it makes sense. But that means you have to know the prices that condos are going for, as well as what rentals for the condos would be. A Realtor is your best source. But a neat online service for rentals that I've found fairly accurate is http://www.rentometer.com.