Driving in Interlaken is very safe and easy (the roads are well paved, but driving in the mountains could a challenge). A very good alternative is the public transport, as buses / trains run regularly, are punctual and reliable. From the train station Interlaken West you have connections in all directions.

Generally speaking,the climate is temperate, although extreme weather conditions do occur from time to time. Temperatures rarely exceed 30°C in July and August, or drop below -10°C from December to February. Snowfall varies from year to year but unless the winter is particularly harsh, snow in town rarely lies for more that two or three days at a time. There is however, a fair amount of rain.

Interlaken is safe! Seriously, Switzerland feels safe and so does Interlaken. Since Interlaken is extremely popular amongst wealthy tourists from all over the world (and the region is wealthy in general), I do not have to take extra precautions – you can wear expensive jewellery, bags, and walk around alone by night without having to worry. Interlaken is also great for solo female travellers

Interlaken is expensive – Switzerland is expensive and Interlaken is one of the most expensive parts in Switzerland. But also argue that there are enough things you can do that does not cost much at all or that are even free.
You can pay in Swiss Francs, but € and $ is also widely accepted – however, you are better off by paying in Swiss Francs.