Prince Siddhattha sought out two of the most eminent [guru's], Alara Kalama and Uddaka Ramaputta. From them he learned systems of meditation which, from the descriptions in the texts, seem to have been forerunners of Raja Yoga. The Bodhisatta mastered their teachings and systems of meditation, but though he reached exalted levels of concentration (samadhi), he found these teachings insufficient, for they did not lead to the goal he was seeking.
http://www.accesstoinsight.org/lib/a.../wheel433.html
He then followed the ascetic way of life and found it insufficient, at which point he thought up the middle way, which he pursued to enlightenment.
I think it would be fair to say that he did find his way mostly by himself.
As to endorsing teachers/gurus, Buddha seems to have been very pro-independence, eg -
The Buddha did not praise his own teaching and attack his rivals. Rather, he told them:
It is right for you to doubt; doubt has arisen in you about dubious matters. Come, Kalamas, do not rely on oral tradition, or on the lineage of teachers, or on holy scriptures, or on abstract logic. Do not place blind trust in impressive personalities or in venerated gurus, but examine the issue for yourselves. When you know for yourselves that something is unwholesome and harmful, then you should reject it. And when you know for yourselves that something is wholesome and beneficial, then you should accept it and put it into practice.— AN 3.65
http://www.accesstoinsight.org/lib/a.../wheel433.html
Overall Buddha himself is no guru poster boy, though the concept of needing empowerments and transmissions does seem to have arisen in later schools of Buddhism.