A floating, multi-lumen-catheter retractor system (100; 300; 400; 500; 600; 700; 800; 900; 1050; 1100; 1150) for ease of positioning in a subject for a minimally invasive treatment of the subject, the system comprising: a highly flexible outer tube (105; 305; 405; 505; 605; 705; 805; 1110) configured for guiding a floating channel (110; 310; 410b,c; 710c; 810; 910; 1122, 1124) and a floating endoscope (115; 215; 315; 815; 1200) in an at least substantially floating arrangement within the system, the flexible outer tube having a lumen(406a,b,c; 706; 806, 806c; 1112, 1114, 1116), a proximal end, and a distal end (308; 408; 508; 608; 708; 808); and, the floating channel serving as a guide through which a tool (; 120, 125; 320, 322, 323, 325; 1210; 1220; 1180) is manipulated in a treatment of a target tissue (290; 390; 490; 590; 690; C) in a subject; and, a reversibly-expandable retractor (350; 450; 550; 650; 1050) that expands to form a treatment space (160; 360; 460; 560; 660; 1060; 1151) in the subject, the retractor configured for the expansion to (i) occur distal to the distal end of the outer tube and (ii) at least substantially render the target tissue aperistaltic for the treatment; wherein, during a use of the system, the floating channel is (iii) at least substantially attached to the lumen of the outer tube at a first proximal location and a first distal location and (iv) at least substantially floating in the lumen of the outer tube between the first proximal location and the first distal location; the floating endoscope is (v) at least slidably-attached to the lumen of the outer tube at a second proximal location and a second distal location and (vi) at least substantially floating in the lumen of the outer tube between the second proximal location and second distal location; and, the increased flexibility of the floating arrangement facilitates an ease of positioning the system in the subject for the treatment of the target tissue. a highly flexible outer tube (105; 305; 405; 505; 605; 705; 805; 1110) configured for guiding a floating channel (110; 310; 410b,c; 710c; 810; 910; 1122, 1124) and a floating endoscope (115; 215; 315; 815; 1200) in an at least substantially floating arrangement within the system, the flexible outer tube having a lumen(406a,b,c; 706; 806, 806c; 1112, 1114, 1116), a proximal end, and a distal end (308; 408; 508; 608; 708; 808); and, the floating channel serving as a guide through which a tool (; 120, 125; 320, 322, 323, 325; 1210; 1220; 1180) is manipulated in a treatment of a target tissue (290; 390; 490; 590; 690; C) in a subject; and, a reversibly-expandable retractor (350; 450; 550; 650; 1050) that expands to form a treatment space (160; 360; 460; 560; 660; 1060; 1151) in the subject, the retractor configured for the expansion to (i) occur distal to the distal end of the outer tube and (ii) at least substantially render the target tissue aperistaltic for the treatment; wherein, during a use of the system, the floating channel is (iii) at least substantially attached to the lumen of the outer tube at a first proximal location and a first distal location and (iv) at least substantially floating in the lumen of the outer tube between the first proximal location and the first distal location; the floating endoscope is (v) at least slidably-attached to the lumen of the outer tube at a second proximal location and a second distal location and (vi) at least substantially floating in the lumen of the outer tube between the second proximal location and second distal location; and, the increased flexibility of the floating arrangement facilitates an ease of positioning the system in the subject for the treatment of the target tissue.