You can do most of that in Excel.
Column A - item
Column B - weight
Column C - pannier location (could even set up a pick list using Validation)
And then you could use formulas to calculate your items 3, 4, and 5. Your item 5 would only be possible if, as a part of your pannier location in Column C, you indicated whether the items would be placed high or low, and you could designate rack bag and handlebar bag as high.
Excel would allow you to change the information in Column C, and your formulas would automatically update.
I could probably whip something like that up in an evening.