Investors & landlords

Yes, if the vacation rental condo was held out for rent (even if you had no rental income), you would include the property expenses on your tax return. (See IRS Pub 527: "Vacant rental property")

Regarding Schedule C versus Schedule E:

IRS Pub 527 states "If you provide substantial services that are primarily for your tenant's convenience, such as regular cleaning, changing linen, or maid service, report your rental income and expenses on Schedule C (Form 1040). Substantial services do not include the furnishing of heat and light, cleaning of public areas, trash collection, etc." 

This is interpreted as running a hotel-like business, with tenant services. If you rent a furnished condo (with kitchen items and linen, for instance), you are not necessarily running a hotel. But if you change the linen and/or provide maid services during the tenant's stay, then this could be considered running a hotel, and the activity should be reported on Schedule C.

If you believe you are not running a hotel-like business, the vacation condo rental may be reported on Schedule E.

The easiest way to find either schedule in TurboTax Online is to go to My Account >> Tools >> Topic Search. Type in "schedule e" or "schedule c", click the topic in the drop-down list, then click "Go." This will take you directly to the start of this section.