UserForm For An Expense Report

I have an expense report with one row labeled as "Auto", and 7 columns labeled with Sunday, Monday, Tuesday, etc. I'd like to double-click a cell within that row and have a userform (or something else) pop up with 2 spots for data entry: "Personal" and "Company". A user would enter dollar amounts in one or both fields. After they're finished, I would like the total of what they entered to populate the cell that was double-clicked, but still have that breakdown available or even be able to change it by re-double-clicking the cell. Is that even possible?

To add complication, at the end of the row are two additional columns that total personal and company expenses. I'd have to have all personal expense amounts sum together in its column, as well as all company expenses sum together in the other column.