Accounting for fees in calculating returns?

[Bill Ramsour]

I'm new to these forums, so apologies if this is the wrong section or a repeat (I'm betting on repeat).  

Short version: when calculating return on a mid- to long-term rental property what sorts of fees do you account for?

Long Version: I'm trying to work out very rough models of what sorts of returns I should expect so I can better shop for deals.  Say my starting situation is this: $50k down on a $200k single-family rental property, giving me a $150k mortgage.  After 5 years of break-even rental income, lets say the house is worth $230k and I now owe $135k on the mortgage.  Without accounting for any fees and such, this would show $50k turning into $95k.  BUT, that's in a magical world where I sell the house like I was selling a book at a garage sale.  

So if we pretend the above could happen... how much should I expect to lose at the purchase, and how much at the sale?  I assume the $200k house will actually cost me an extra percent or two in fees and closing costs (making the mortgage more like $154?).  Then at the sale end, I'll pay 6% to realtors, plus other fees and such, right?  So my math becomes:

Starting mortgage = 200,000 * (1 + <fee%>) - 50,000
Ending value = 230,000 * (1 - <fee%>) - <remaining mortgage>

If I expect 2% at the front end, and 8% at the back, this becomes a starting mortgage of $154k, final mortgage at about $140k, and a final result of turning that $50k into about $72k.  In my spreadsheet I'd have more exact math, I'm just simplifying for discussion sake.

So, you account for these fees when doing your projections?  What fees do you expect?  And I guess while I'm at it: Are there tricks for reducing these fees?

Thanks, 
Bill