i need 4 days off work. What excuse should i use?

I have an opportunity to train at another job, with a meeting afterwards 2 c how we like each other. I presently work at a tiny company- we all know each others' life storys. I do have family in another state, i could invent a relative (funeral) (live in same town as boss, could run into each other) or is honesty the best policy? Present boss knows I'm miserable there, but doesnt know I've been looking.