The dates you can't move — and whether the days between them fit
A flight home on the 8th, friends meeting you in Nashville on the 7th. Tell My Trip about a date like that and it lays out the days between here and there at your own speed, counts the locks, and says plainly whether they fit.

Three kinds of date

My Trip → Dates (Tools → Plan Around Your Dates opens the same card). Add a date offers three: Be somewhere by a date, Away from the boat, Start from a place on a date. Add several and they chain.
Fits, Tight, or Does not fit

Grand Haven to DuSable by the 20th: Fits — 95 nm, one lock, 3 travel + 1 rest day, leave by Thu, Sep 17. DuSable to Nashville by October 7th: Does not fit — 676 nm, 13 locks, 21 travel days at 7.5 kn × 6 h, arriving the 10th. The rest days are your own habit, 14 lay against 23 travel in your log.
Two numbers, not one
Four locks carry a tow-queue wait. Counted in the verdict, then said again without them: 17 travel days, arrive Tue, Oct 6 — fits.
Show the days

Night by night, with depth where we hold one and "depth not on file" where we don't. October 6th is 1.2 nm and 37 hours at Kentucky Lock.
It reads your trip; it never rewrites it
Nothing changes until you press Set as next destination or Make it an away span.
What it cannot do yet
Rest days come from your pace, not the forecast; and it can tell you a date doesn't fit, not yet what would.