As I understand things, I'll be able to fairly simple calculate values using factors from far flung tables as long as they're related (via P/F key relationships). So, am I right in thinking calculations such as:
subcontractors.costperacre * (stands.areainsquarefeet/43,560) will be quite feasible as will more removed cases?

Would a calculation involving a value from another branch work? For instance, given this ERD, will I be able to conduct an operation like:
(subcontractors.costperacre WHERE "filter" - subsidyagents.subsidyperacre) * stands.area/43,560

sure, in a join query

Thanks Rudy,

Then, I'm off and running (or more like toddling). I'll finish my field specs and view specs and move onto the next stage.