is it correct to go R1 - R2- R3 -R4?
No. If this is pure IP forwarding (no MPLS and no tunnels of any sort: GRE, IPIP, IPSec etc) then when packet destined to R4 hits R2, then R2 has 2 choice routes:
- INTRA area 10 route from R4 via R5
- INTER area 0 route from R3
According to RFC 2328 section 11, INTRA area route is preferred and R2 will send this packet to R5 and R5 will forward to R4.