Chicago O’Hare Options

The nearest and dearest is speaking at a vet conference in Chicago later this year (end of Oct/ early Nov).
She will be reimbursed for rtn economy flights, but trying to find best route from London. Is allowing the VA site to create connections and options with Delta on their website the best idea. Or should we break it down into segments / sectors individually ourselves?
BA /Aa offer direct flights with a checked bag for 301
Va/delta offer econ light (no bag) and connection for. 324
want to get the airmiles selfishly haha
She will be reimbursed for rtn economy flights, but trying to find best route from London. Is allowing the VA site to create connections and options with Delta on their website the best idea. Or should we break it down into segments / sectors individually ourselves?
BA /Aa offer direct flights with a checked bag for 301
Va/delta offer econ light (no bag) and connection for. 324
want to get the airmiles selfishly haha