What is the difference between communism and juche ideology?

Juche is, in layman's terms, a derivation of Marxism-Leninism with Maoist influences. It was first introduced by Kim Il-Sung at the Meeting of Leading Personnel of the Young Communist League and the Anti-Imperialist Youth League held at Kalun in June 1930.
It is primarily concerned with the laws of the social movement and the development of socialist ideology under the socialist socio-economic system. Marxism-Leninism, as well as Dialectical and Historical Materialism, are assumed by this ideology, so you should have some knowledge about these topics if you want to learn about the Juche Idea.
Kim Jong-Il talks about the foundations of Marxism-Leninism inherent in the Korean revolutionary philosophies and ideologies in On Correctly Understanding the Originality of Kimilsungism:

Kimilsungism was founded and has been developed in the course of safeguarding and embodying the ideological and theoretical achievements of Marxism-Leninism. The Juche Idea itself is an idea discovered in the process of the revolutionary struggle waged under the banner of Marxism-Leninism; it is an idea which has opposed all trends of idealism and metaphysics and strictly adhered to the materialistic and dialectic stand. The revolutionary theory of Kimilsungism is also a theory which was founded and enriched in the course of protecting the revolutionary quintessence of Marxist-Leninist theory from bourgeois and opportunist theories and creatively applying and developing it in line with the requirements of the revolutionary practice of our times.

The Juche Idea is concerned primarily with elucidating the attributes of man which drive social movement. These are defined as independence, creativity, and consciousness, which complement and require each other. These attributes are explained bit by bit, shown to differentiate man from animals through his conscious, creative activity which frees him from the fetters of nature and society by advancing in the progressive struggle for communism.
If you want to talk about the economic or social policy of the DPRK, the concept you're looking for is primarily Kimilsungism-Kimjongilism, not the Juche Idea.
A primary point of the Juche Idea is that each revolution must be carried out by its own people, rather than by a foreign power attempting to dominate the younger revolution towards its own interests.

Juche ideology is standing on three pillars

1.Independent economy

2.Independent political culture.

3.Sociel Independence.

But it evolved through generation such that north korea is economically independent,politically independent and also socially ,made them isolated from outer world from economical,political and social point view.Thus they created a country full of people brainwashed by their leaders.

Now coming to communism it says equality and govt. interference in the economy,society to make a balance in the society.

If we compare both of this ,communism doesn't say to get isolated from other entities whereas the north korea is in such a stage right now.

What is it like to travel and explore new places by oneself? Why go alone?

When I hit the road, people always asked me why I was travelling alone. I just told them all that I wanted some lone time. But apart from solitude, there can be many reasons that people travel alone.People are never alone. They make friends