Only not to leave unaswered the well known and easy part of the question, i.e.

> especially in the case that the Artinian ring is also a principal ideal ring (two-sided Artinian and two-sided principal

The case of artinian PIR (and more generally of artinian serial rings) was solved (Koete, Asano and others) in the years just before WW2 and was included in the first of Jacobson's books (The theory of rings, 1943). These are of finite representation type, all irriducible module are uniserial (and if I remember correctly even modules of infinite lenght are direct sums of the uniserials of finite lengh, but I think this was shown after WW2. Faith, Algebra II and "rings and things" shoud have modern references).

The case of artinian PIR (which are the same as proper homomorphic images of Dedekind domains or PID, even non commutative ones, so the finitely generatd "bounded" modules over such domains are exactly the f.g. modules over artinian PIR): artinian PIR are exactly the finite direct sum of matrix rings over CPU rings (CPU: a ring where each ideal is two sided, and thei form a finite chain. They are the proper homomorphic images of discrete valuation domains, and conversey these domains are the inverse limit of a sequence of CPU). 

The category of (f.g.) modules over such a ring is then, by morita equivalence, the category of (f.g.) modules over a finite direct sum of CPU. If a CPU has lengh $n$ then there are exactly $n$ indecomposable nonzero modules, and they are exactly the nonzero submodules of the CPU and also exactly the proper homomorphic images. Two distinct CPU in the direct decomposition of the PIR (even two copies of the "same" CPU up to isomorphism) give indecomposable modules with zero Hom among them.

[My interest in such matters comes from the Baer / Inaba / J\'onsson - Monk coordinatization theorem. The fact that "primary lattices" are simple or finite chains gives, together with the basic theory of such lattices, a nice "incidence geometry" description of the
above facts about indecomposables]

[For the more general artinian serial rings, the description of the ring and of the indecomposable modules is more complicated, but quite explicit; there are several cases to discuss].