I think the two words are similar in most cases except following difference :
本来or 原本 emphasize the initial circumstance more . 他本来/原本的想法是要去美国。(initial thinking)
原来 just describs the previous circumstance . 在经商之前,他原来是名教师。(he was a teacher before he was in busness. If we use 本来/原本 here , it imply his first job was a teacher.)
原来 also means "actually" sometimes.我以为她在和男朋友打电话,最后才知道那个人原来是她爸爸。(the one on other side of the phone is her father actually, not her boyfriend.)