What should I avoid in Stockholm?

Start with Arlanda, because the first mistake tends to happen about 40 km north of the city. The Arlanda Express reaches Stockholm Central in roughly 18 minutes, but a one-way adult ticket currently runs around 340 SEK, close to 34 USD at 10.01 SEK to the dollar. The SL commuter train from the same airport takes about 40 minutes and costs roughly 190 SEK with the Arlanda station fee included, while Flygbussarna coaches to Cityterminalen sit below that on price and take around 45 minutes. Take the commuter train. As for cabs, skip any car at Terminal 5 that is not Taxi Stockholm, Sverigetaxi, or Taxi Kurir. Swedish taxi fares are deregulated, so each car sets its own tariff and posts it on a yellow sticker in the rear window. Read that sticker before the door closes. A comparison price above roughly 400 SEK is your signal to walk to the next car in the rank.

Gamla Stan is worth two hours, not two dinners. Västerlånggatan is a corridor of Viking-helmet magnets and plastic Dala horses, loud with rolling suitcases on wet cobbles by 11:00. The restaurants ringing Stortorget, the square beside the Nobel Prize Museum, tend to charge 250 SEK or more for meatballs, while the same plate is likely to cost about 150 SEK at a weekday lunch on Södermalm. Look for the words "dagens lunch" on a chalkboard between 11:00 and 14:00, Monday to Friday: a set plate for around 130 to 170 SEK, usually with salad, bread, and coffee. Köttbullar are meatballs with cream sauce and tart lingonberry, and Toast Skagen is cold prawns in dill mayonnaise on butter-fried bread. Both are safe first orders. Surströmming, the fermented Baltic herring of YouTube gagging videos, is a northern August ritual eaten outdoors, and no Stockholm kitchen is likely to push it on you. If you do stay to eat on the island, walk one street east to Österlånggatan, where the warm cardamom smell from the bakeries carries further than the sales pitches.

Skip the Forex desk at Stockholm Central. The city runs on cards, and plenty of cafes and museums, the ABBA Museum on Djurgården among them, refuse cash outright. Skip the hop-on hop-off bus pass while you're at it: tap a contactless card at any SL gate for about 43 SEK and you get 75 minutes on the tunnelbana, buses, trams and the Djurgården ferry from Slussen, and that ferry gives you the same cold wind off Saltsjön and the same diesel thrum underfoot as the paid sightseeing boats. Come evening, anything stronger than 3.5% comes from Systembolaget, the state shops, which close around 15:00 on Saturdays and stay shut on Sundays. The Icebar at Hotel C near Central Station sells about 40 minutes in a borrowed cape at minus 5°C for well over 200 SEK. Stockholm this week is 9.1°C and feels like 7.5°C, free of charge.

Don't stack the Vasa Museum, Skansen and Drottningholm Palace into your first day on five hours of sleep. Vasa and Skansen share Djurgården and sit about a 10-minute walk apart, so pair those two. Drottningholm is out in Ekerö Municipality, close to an hour each way by boat from Stadshuskajen beside Stockholm City Hall, and it needs its own half day. The Vasa queue tends to be longest between 11:00 and 14:00 in July and August, so go at opening. The changing of the guard at Stockholm Palace pulls a thick summer crowd, so arrive 20 minutes early or skip it. The city is calm, and TTDI scores solo-traveler safety at 7.2/10 (see the TTDI Solo-Safety Index), but pickpockets still work T-Centralen, Drottninggatan and the Gamla Stan souvenir strip in summer, so keep your phone off the cafe table. One more local rule: the marked cycle lanes on Götgatan and Skeppsbron are not pavement, and commuters ring a bell once before they pass at around 25 km/h.