Lookup value based on closest date either side of a date

Hi All.

The attached contains two tables: 'Visits' and 'Samples'. The ID field on both tables is unique to an individual, and there may be multiple instances (again on both tables) where the individual has >1 visit or sample reported.

I'm trying to join the most appropriate* Sample Date and the associated Sample Score (from the 'Samples' table) to each visit (on the 'Visits' table).

*Appropriate = the 'Sample Reported Date' that is nearest either side of the 'Visit Date'.

I've typed what I would hope to see in columns C:D. If possible, please could the manual calculations in C:D be replaced with the appropriate forumlae?

Thanks so much for any help and let me know if I can clarify anything.