We arrive in Basel, then to Interlaken for four days, then to Kreuzlingen/Konstance Germany to rent a car.. Is the Swiss card the way to go and does it work entering Switzerland in one city and leaving Switzerland at another city..
To answer you rsecond question first, yes, you can depart from a different city than the one you used for entry. As for whether the Swiss Card is the "way to go", that depends on whether you will be using the half-fare discount feature while at Interlaken to ride lifts and boats. Assuming you are, then the Swiss Card is what I would do in this scenario. The cost of travel Basel to Interlaken Ost is 58 CHF and from Interlaken ost to Konstanz is 88 CHF, so you would get that included, plus the Half-Fare card feature which is worth 120 CHF. So 266 CHF value for $221. Sounds good to me.