Ok, say someone was going to arrive in London on a Sunday afternoon and leave the following Wednesday afternoon. If they are riding the red buses only (not the tube or trains) is it cheaper to get an oyster card or a travel card? An oyster card, right? They've discontinued the 3 day travel cards? I ~think~ a travel card goes by days, not 24 hour periods, so I'd have to buy a travel card for each of Sun, Mon, Tues, and Wednesday even if I only rode the bus once on Sunday and once on Wednesday. Is that correct?
With the oyster card they'd just hit the card for no more than £7-ish pounds per day on days I used the bus? I believe that the red bus has no zone restrictions, so if we spent most of our time in zone 1, but were staying in, say, zone 3, it wouldn't make any difference fare-wise?
Is there any advantage, other than convenience, to buying a visitor oyster card before arriving, rather than a "regular" oyster card when we get there?
(Sorry, it's been 10 years since I've been in London and I've just spent a half hour trying to understand the options from reading various websites. The last time I was there I just bought an all-day paper bus ticket at the news agent's.)