Ultranav is nice to provide you with speeds etc, but it doesn't address close-in obstacles.
You still lack information for the gap between certification 2.4% and TERPS 3.3%.
The only way to be 100% safe is airport analysis. I find that aircraft performance group (APG) does an impressive job at providing airport analysis specific to your aircraft. It is the single best way to insure that you carry the maximum possible payload and still clear the obstacle.
As for flightplanning, I use flightplan.com. I wish I could afford Jeppview or Jepp's internet flight planner, but i'm too cheap.
What does everyone use to find hotels with 24 hours notice? (aside from just calling the FBO and asking)