I'm pretty handy--a pretty good painter--am I getting in over my head?

[Horse with no Name]

There is a house here in town they are taking bids on painting the interior. I have done my own house--completely--and it is over 2000 sq ft.
There is a 4300 sq ft home that needs the interior painted.
I could really use the extra money to pay some bills off, so I found out what the bids are ($14k-18K) and I bid $8500. I priced paint at Sherwin Williams for about $1k.
I find I have free time right now with kids out of school and could really use the cash.
Is this a project I should defer to the professionals?

[fortyfeetunder]

1. Wall conditions might be what you want to investigate

What are the conditions of the interior walls that you'd want to investigate?
For example: kitchen (grease, moisture) and bathroom (mold, water damage)

Will you have to do more than just painting? Like spackling, wall repair, patching?

Ceilings: what type ceilings? Will you have to use scaffolding to reach ceilings?

How long since the last paint job? Will you have to prime walls before painting?

That's the underlying stuff I can think of...