Where it lands depends on which half of the city you are aiming at, and the two halves fail in different ways. Up above Bonita Avenue — Via Verde around the country club, the Marchant streets, the frontages that run toward San Dimas Canyon and along the Puente Hills flank — houses sit back from the road behind hedges and long driveways, some of the newer clusters gate at the street, and the thing that stops a delivery is a code nobody wrote in the notes. Below, in the tract grid that runs from Cataract Avenue out along Arrow Highway toward Lone Hill, the addresses are easy to find, but a large share of the younger romantic volume lives in apartment courts and condominium clusters where the driver needs a unit number and a word about the lobby. Neither is hard. Both are only easy if you tell us in advance.
The commute is the other half of the timing problem, and in San Dimas it is specific. The city is built around the interchange where the 210 meets the 57, and the working population splits between them — south on the 57 toward Diamond Bar, Brea and the Orange County job centers, or west on the 210 toward Pasadena and the basin, with a third group heading east on the 10. Those are all long drives. Someone who leaves Via Verde at seven in the morning may not be back until half past six, which makes the early-afternoon window the wrong one and the mid-to-late afternoon window the right one. If the flowers are the surprise, put your own mobile number in the order rather than the recipient's, and if the arrival time is the point, take the standard tier. This is the one occasion where paying five dollars more buys the whole effect.
A meaningful share of the romantic volume here is student and young-professional rather than married-thirty-years, because San Dimas sits in the middle of a dense cluster of campuses. The University of La Verne is two miles east; Cal Poly Pomona is about six miles south off Temple Avenue; Mt. San Antonio College is in Walnut, close to where Royal Florists works on Amar Road; Citrus College is four miles northwest in Glendora; and the Claremont Colleges sit roughly eight miles east. Deliveries to any of them go to a department office, a mailroom or a residence-hall package desk, and the recipient's full legal name matters more than the room number — package desks match names, not nicknames. For an off-campus apartment, which is where most of it actually goes, treat it like any other locked-lobby address and include the unit.