Calcitriol, Cisplatin, and Gemcitabine Hydrochloride in Treating Patients With Advanced Solid Tumors That Cannot Be Removed by Surgery

Inclusion Criteria:

* Patients with a diagnosis of advanced unresectable non-hematological malignancy that has no known standard of care or for which the use of gemcitabine plus cisplatin constitutes a reasonable option
* Have an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-1
* White blood cell (WBC) \>= 3.0 x 10\^9/L
* Neutrophils \>= 1.5 x 10\^9/L
* Platelets \>= 100 x 10\^9/L
* Hemoglobin (Hgb) \>= 10 g/dL
* Bilirubin =\< institutional upper limit of normal (ULN)
* Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \< 2.5 x institutional ULN unless metastatic to liver in which case AST and ALT should be \< 5 x institutional ULN
* Creatinine =\< 1.5 x institutional ULN
* Corrected calcium =\< institutional ULN (corrected calcium = (4- Albumin) x 0.8 + calcium)
* Patients of child-bearing potential must agree to use acceptable contraceptive methods (e.g., double barrier) during treatment
* Patient or legal representative must understand the investigational nature of this study and sign an Independent Ethics Committee/Institutional Review Board approved written informed consent form prior to receiving any study related procedure
* No treatment with investigational agents within 4 weeks prior to study drug administration, except patients receiving targeted therapies such as kinase inhibitors with half-lives \< 48 hours may be treated if \> 14 days have elapsed after the last dose and related toxicities have recovered to =\< grade 1
* No chemotherapy within 4 weeks prior to study treatment administration; nitrosoureas and mitomycin C are not allowed within 6 weeks prior to initiation of study treatment
* Palliative radiation, including whole brain radiation therapy (WBRT), is allowed prior to enrollment as long as it is completed \> 2 weeks from initiation of study treatment, and provided patient has recovered from treatment toxicities to =\< grade 1
* Patients should be able to take oral medications

Exclusion Criteria:

* Known hypersensitivity to any of the study drugs involved
* Brain metastases are excluded unless treated and shown to be controlled more than 1 month from after craniotomy or more than 2 weeks after gamma knife radiosurgery and not associated with central nervous system (CNS) symptoms
* History of clinically significant hypercalcemia
* Evidence of nephrectomy
* History of (within 24 months prior to enrollment) of kidney, ureter, or bladder stones with clinically significant sequelae (e.g. (painless gross hematuria; pain with or without infection; hydronephrosis, etc); patients with otherwise stable non-occluding kidney stones regardless of stone type incidentally found in computed tomography (CT) scans are eligible; patients with prior history of uric acid stones are eligible regardless of time of onset
* Unwillingness to stop calcium supplementation (during the first cycle of treatment) or vitamin D supplementation throughout the study
* Thiazide (e.g HCTZ, Hydrochoirthiazide) or digoxin therapy (e.g Lanoxicaps, Lanoxin)
* Pregnant or nursing female patients.
* Unwilling or unable to follow protocol requirements
* Any condition which in the investigator's opinion deems the patient an unsuitable candidate to receive study drug
* Received an investigational agent within 4 weeks prior to enrollment, except patients receiving targeted therapies such as kinase inhibitors with half-lives \< 48 hours may be treated if \> 14 days have elapsed after the last dose and related toxicities have recovered to =\< grade 1
* Nut allergy