You can also go to an 'ENROLLED AGENT who in my opinion is the best place to go regarding taxation. 

You didn't go into real estate to be burdened down with all the back-office/no value-add tasks such as tax preparation.With that said - there are many accountants on this messageboard who specialize in real estate taxation and capable of helping you.

You open yourself to more accountants who specialize in real estate taxation if you are open to the idea.

You will be credited by the seller for the property tax at closing (they will pay what they owe to date).

@John Thedford,401k is a tax-deferred vehicle, income and gains from investments would not be subject to taxation, unless the income is UBTI (Unrelated Business Taxable Income), which in turn would be subject to UBIT. 

Make sure you work with an accountant who is familiar with the taxation of both.Many accountants are busy now as there is 3 weeks left in this tax season.

you get many benefits of running an LLC as a business for your rental property - 1) limited your personal liability 2) keep your properties separate from one another 3) pass thru taxation to your personal return 4) you separate personal from business expenses (some are now deductible whereas the were not before 5) if you have multiple owners of a property, they are essential umbrella policies still have limits - your personal assets could still be exposed - creating and running an LLC property will ensure your personal property is never exposeddisclaimer - I am not a CPA nor an attorney, seek professional advice for your state

You may be required to file non-resident state tax returns with those states.There are approximately 20+ accountants on the biggerpockets message board who specialize in real estate taxation.

@John ReedA solo 401(k), as a tax-exempt entity, does have exposure to two forms of taxation. 

Removing a property from the C Corp, to refi or for whatever reason, would generally be a taxable event.Then you have to contend with the personal holding company (PHC) tax that you probably will have exposure to.Then you have consider double taxation, as @Natalie Kolodij mentioned.